- not sufficient; lacking in what is necessary or required: an insufficient answer.
- deficient in force, quality, or amount; inadequate: insufficient protection.
- not sufficient; inadequate or deficient
late 14c., from Old French insufficient (14c.), from Latin insufficientem (nominative insufficiens) “insufficient,” from in- “not, opposite of” (see (1)) + sufficientem (see ). Originally of persons, “inadequate, unable;” of things, from late 15c. Related: Insufficiently.
- Not sufficient.
- Incapable of proper functioning.