insufficient

UK: /ˌɪnsəˈfɪʃ^ənt/ US: /ˌɪnsəˈfɪʃənt/ ,(in′sə fish′ənt)

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

in•suf•fi•cient /ˌɪnsəˈfɪʃənt/   adj. 

1. not sufficient;
   lacking in what is necessary or required:
   insufficient funds.

in•suf•fi•cient•ly, adv. 

WordReference Random House Unabridged Dictionary of American English © 2026

in•suf•fi•cient  (in′sə fish′ənt), adj. 

1. not sufficient;
   lacking in what is necessary or required:
   an insufficient answer.
2. deficient in force, quality, or amount;
   inadequate:
   insufficient protection.

• Late Latin insufficient- (stem of insufficiēns). See in-³, sufficient
• Middle English 1350–1400

in′suf•fi′cient•ly, adv. 
Synonyms

• 1. inadequate, scanty, deficient.

Collins Concise English Dictionary © HarperCollins Publishers::

insufficient / ˌɪnsəˈfɪʃənt/ adjective

1. not sufficient; inadequate or deficient

ˌinsufˈficiently adverb