formidable

UK: /fə^rˈmɪdəb^əl/, /ˈfɔː^rmɪdəb^əl/

US: /ˈfɔrmɪdəbəl/

US: (fôr′mi də bəl)

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

for•mi•da•ble /ˈfɔrmɪdəbəl/   adj. 

1. causing fear, awe, or concern:
   a formidable opponent.
2. of awesome size, difficulty, etc.:
   a formidable problem.

for•mi•da•bly, adv. 

WordReference Random House Unabridged Dictionary of American English © 2025

for•mi•da•ble  (fôr′mi də bəl), adj. 

1. causing fear, apprehension, or dread:
   a formidable opponent.
2. of discouraging or awesome strength, size, difficulty, etc.;
   intimidating:
   a formidable problem.
3. arousing feelings of awe or admiration because of grandeur, strength, etc.
4. of great strength;
   forceful;
   powerful:
   formidable opposition to the proposal.

• Latin formīdābilis causing fear, equivalent. to formīd- (stem of formīdāre to fear) + -ābilis -able
• French
• late Middle English 1400–50

for′mi•da•ble•ness, for′mi•da•bil′i•ty, n. 
for′mi•da•bly, adv. 
Synonyms

• 1. dreadful, appalling, threatening, menacing, fearful, frightful, horrible.

Antonyms

• 1. pleasant.

Collins Concise English Dictionary © HarperCollins Publishers::

formidable / ˈfɔːmɪdəb^əl/ adjective

1. arousing or likely to inspire fear or dread
2. extremely difficult to defeat, overcome, manage, etc: a formidable problem
3. tending to inspire awe or admiration because of great size, strength, excellence, etc

Etymology: 15th Century: from Latin formīdābilis, from formīdāre to dread, from formīdō fear

ˈformidably adverb