deform

UK: /dɪˈfɔː^rm/ US: /dɪˈfɔrm/ ,(di fôrm′)

WordReference Random House Learner's Dictionary of American English © 2026

de•form¹ /dɪˈfɔrm/   v. [ ~ + obj]

1. to mar the natural form of; disfigure:
   a body badly deformed by a birth defect.
2. to mar the beauty of;
   spoil:
   How could they deform such a beautiful landscape?

de•for•ma•tion /ˌdifɔrˈmeɪʃən/  n. [uncountable* countable] See -form-.

WordReference Random House Unabridged Dictionary of American English © 2026

de•form¹  (di fôrm′), v.t. 

1. to mar the natural form or shape of;
   put out of shape;
   disfigure:
   In cases where the drug was taken during pregnancy, its effects deformed the infants.
2. to make ugly, ungraceful, or displeasing;
   mar the beauty of;
   spoil:
   The trees had been completely deformed by the force of the wind.
3. to change the form of;
   transform.
4. Geology, Mechanics to subject to deformation:
   The metal was deformed under stress.

v.i. 

5. Civil Engineering to undergo deformation.

• Latin dēfōrmāre, equivalent. to dē- de- + fōrmāre to form
• Middle English deformen 1350–1400

de•form′a•ble, adj. 
de•form′a•bil′i•ty, n. 
de•form′a•tive, adj. 
de•form′er, n. 
Synonyms

• 1. misshape. See mar. 
• 2. ruin.

de•form²  (di fôrm′), adj. [Archaic.]

1. deformed;
   ugly.

• Latin dēformis, equivalent. to dē- de- + -formis -form
• Middle English defo(u)rme 1350–1400

Collins Concise English Dictionary © HarperCollins Publishers::

deform / dɪˈfɔːm/ verb

1. to make or become misshapen or distorted
2. (transitive) to mar the beauty of; disfigure
3. to subject or be subjected to a stress that causes a change of dimensions

Etymology: 15th Century: from Latin dēformāre, from de- + forma shape, beauty

deˈformable adjective