Antonyms of adj inefficient

2 senses of inefficient

Sense 1
inefficient (vs. efficient) -- (not producing desired results; wasteful; "an inefficient campaign against drugs"; "outdated and inefficient design and methods")

efficient (vs. inefficient) -- (being effective without wasting time or effort or expense; "an efficient production manager"; "efficient engines save gas")
        => businesslike -- (exhibiting methodical and systematic characteristics that would be useful in business)
        => cost-efficient, cost-effective -- (productive relative to the cost)
        => economic, economical -- (using the minimum of time or resources necessary for effectiveness; "an economic use of home heating oil"; "a modern economical heating system"; "an economical use of her time")
        => expeditious -- (marked by speed and efficiency)
        => high-octane -- (used of gasoline; having a high octane number)
        => streamlined -- (made efficient by stripping off nonessentials; "short streamlined meetings"; "a streamlined hiring process")

Sense 2
ineffective, inefficient -- (lacking the ability or skill to perform effectively; inadequate; "an ineffective administration"; "inefficient workers")

INDIRECT (VIA incompetent) -> competent -- (properly or sufficiently qualified or capable or efficient; "a competent typist")

Similarity of adj inefficient

2 senses of inefficient

Sense 1
inefficient (vs. efficient) -- (not producing desired results; wasteful; "an inefficient campaign against drugs"; "outdated and inefficient design and methods")
       => uneconomical, wasteful -- (inefficient in use of time and effort and materials; "a clumsy and wasteful process"; "wasteful duplication of effort"; "uneconomical ebb and flow of power")
          Also See-> incompetent#2; ineffective#1, uneffective#1, ineffectual#1

Sense 2
ineffective, inefficient -- (lacking the ability or skill to perform effectively; inadequate; "an ineffective administration"; "inefficient workers")
       => incompetent (vs. competent) -- (not qualified or suited for a purpose; "an incompetent secret service"; "the filming was hopeless incompetent")