how do you do

US: (hou′də yə do̅o̅′)

WordReference Random House Unabridged Dictionary of American English © 2025

how′ do you do′, 

1. (used as a conventional greeting).

how-do-you-do  (hou′də yə do̅o̅′), n., pl. -dos. [Informal.]

1. a greeting; salutation:
   She smiled and gave him a how-do-you-do fit for a king.
2. an awkward or unpleasant event or situation:
   It's a fine how-do-you-do that they've refused to help us out.

Also, how-de-do  (hou′dē do̅o̅′). 

• 1625–35

Collins Concise English Dictionary © HarperCollins Publishers::

how do you do sentence_substitute

1. Also: how do?, how d'ye do? a formal greeting said by people who are being introduced to each other or are meeting for the first time

noun how-do-you-do

1. a difficult situation

WordReference Random House Learner's Dictionary of American English © 2025

how¹ /haʊ/   adv. 

1. [used in questions]
   • in what way or manner;
     by what means:
     How did the fire start?
   • to what extent, degree, etc.:
     How difficult was the test?
   • at what amount or rate or in what measure or quantity:
     How much is this? How are these tomatoes sold?
   • in what state or condition:
     How is the baby?
   • for what reason;
     why:
     How can you say that?
   • to what effect;
     with what meaning:
     How is one to interpret such actions?
   • what:
     How do you mean?
   • by what title or name:
     How does one address the president?
   • in what form or shape:
     How does the demon appear in the first act?
2. This word is used to express strong feeling:
   How sweet it is! How I love this mountain scenery!

conj. 

3. the manner or way in which:
   I couldn't figure out how to solve the problem.
4. about the manner or condition in which:
   Be careful how you act.
5. in whatever manner or way;
   however:
   You can dress how you please.
6. Informal Terms that:
   She told us how he was honest and could be trusted.

n. [countable]

7. a question concerning manner or method:
   too many hows about the way this happened.

Idioms

8. Idioms and how! [Informal.] certainly:
   Am I happy? And how!
9. Idioms how about? This phrase is used to mean "What do you think or feel regarding (the next thing mentioned)?'' or "What is your response to (the next thing mentioned)?'':
   If they don't have pumpkin pie, how about apple?
10. how are you? This phrase is used as a greeting to someone already known to the speaker:
    I haven't seen you lately; how are you?
11. how come? [Informal.] This phrase introduces a question meaning "how is it that? why?,'' but, unlike similar questions, there is not a change in word order:
    How come you don't visit us anymore?
12. how do you do? This expression is used when one is introduced to someone in a formal situation:
    "This is my husband, Mr. Smith.''— "How do you do, Mr. Smith?''
13. Idioms how so? how does it happen to be so? why?:
    You left early? How so?

Usage

Compare the use of how in questions (def. 1) and in emphasizing (def. 2). In the questions, the subject comes after the verb:
How did the fire start?
In emphasizing statements, the subject comes before the verb:
How sweet it is!
Also, compare the use of How is/are...? with a similar construction involving what, as in What is/are...like? Both ask a question about a noun or about some state or condition. The expression How is/are...? is used to ask about temporary or changing states or conditions of things:
How is your arm? —A little sore.
How is your sister? She looks a little tired today.
The expression What is/are...like? is used to ask questions about the permanent state, nature, or condition of someone or something:
What is school like in your country?—Well, there is elementary school, what they call gymnasium, and then college or university.
What is your sister like?—She is tough, smart, and works hard.

WordReference Random House Unabridged Dictionary of American English © 2025

how¹  (hou), adv. 

1. in what way or manner;
   by what means?:
   How did the accident happen?
2. to what extent, degree, etc.?:
   How damaged is the car?
3. in what state or condition?:
   How are you?
4. for what reason;
   why?:
   How can you talk such nonsense?
5. to what effect;
   with what meaning?:
   How is one to interpret his action?
6. what?:
   How do you mean? If they don't have vanilla, how about chocolate?
7. (used as an intensifier):
   How seldom I go there!
8. by what title or name?:
   How does one address the president?
9. at what price:
   How are the new cars going, cheaper than last year's models?
10. by what amount or in what measure or quantity?:
    How do you sell these tomatoes?
11. in what form or shape?:
    How does the demon appear in the first act of the opera? How does the medication come?
12. and how! [Informal.] certainly! you bet!:
    Am I happy? And how!
13. Here's how, [Informal.] (used as a toast).
14. how come? [Informal.] how is it that? why?:
    How come you never visit us anymore?
15. Idioms how so? how does it happen to be so? why?:
    You haven't any desire to go? How so?

conj. 

16. the manner or way in which:
    He couldn't figure out how to solve the problem.
17. about the manner, condition, or way in which:
    I don't care how you leave your desk when you go. Be careful how you act.
18. in whatever manner or way;
    however:
    You can travel how you please.
19. Informal Terms that:
    He told us how he was honest and could be trusted.

n. 

20. a question concerning the way or manner in which something is done, achieved, etc.:
    a child's unending whys and hows.
21. a way or manner of doing something:
    to consider all the hows and wherefores.
22. a word formerly used in communications to represent the letter H.

• bef. 900; Middle English how, hu, Old English hū; cognate with Old Frisian hū, ho, Dutch hoe; akin to German wie (Old High German hweo), Gothic hwaiwa

how²  (hou), interj. [Facetious.]

1. Slang Terms (used as a greeting in imitation of American Indian speech.)

• of uncertain origin, originally 1810–20

how³  (hou), n., adj. [Scot. and North Eng.]

1. Slang Terms howe.