Synonyms of inefficient

1 Syllable

slack, weak

2 Syllables

feeblest, feebler, inept, faulty, slipshod, sloppy, feeble, strengthless, helpless, unfit

3 Syllables

untrained, nonexpert, inexpert, unpleasing, unskilled, half-baked, forceless, basket-case, unskillful, prodigal, careless, unable, slack-spined, unfitted, impuissant, slovenly

4 Syllables

unprepared, unqualified, improficient, improvident, extravagant, incompetent, ineffectual, incapable, defeasible

5 Syllables

invertebrate, disorganized, unprofessional, unpersuasive, ineffective, inefficacious, anticlimactic