From Middle French insufficient, from Latin insufficiens. See also in- +‎ sufficient.

• IPA^(key): /ɪnsəˈfɪʃənt/

• Audio (Southern England):

  (file)

• Rhymes: -ɪʃənt
• Hyphenation: in‧suf‧fi‧cient

insufficient

1. An inadequate quantity of; not enough.

   Insufficient time is available to reflect on the problem.

2. (as pronoun) A quantity (of something) that is less than is needed.

   Insufficient of the building remains to determine its age.

insufficient (comparative more insufficient, superlative most insufficient)

1. Not sufficient; of a type or kind that does not suffice, that does not satisfy requirements or needs.

   an insufficient amount;   an insufficient degree

   It is a necessary condition but an insufficient one.

   Synonyms: unsufficient (uncommon), deficient, lacking

2. Not sufficient; lacking competent power or ability; unqualified, unequal, unfit.

   Synonym: unsufficient (uncommon)

   • c. 1587–1588 (date written), [Christopher Marlowe], Tamburlaine the Great. […] The First Part […], 2nd edition, part 1, London: […] [R. Robinson for] Richard Iones, […], published 1592, →OCLC; reprinted as Tamburlaine the Great (A Scolar Press Facsimile), Menston, Yorkshire; London: Scolar Press, 1973, →ISBN, Act I, scene i:

     Brother Coſroe, I find my ſelfe agreeu’d,
     Yet inſufficient to expreſſe the ſame:
     For it requires a great and thundering ſpeech: […]

See deficiency § Usage notes.