imperfect

adjective

im·​per·​fect (ˌ)im-ˈpər-fikt 

1

: not perfect: such as

a

: flawed in form, structure, or function : defective, deficient

an imperfect world

an imperfect system

conclusions based on imperfect data

b

of a flower : having stamens or pistils but not both

c

: lacking or not involving sexual reproduction

the imperfect stage of a fungus

2

: of, relating to, or constituting a verb tense used to designate a continuing state or an incomplete action especially in the past

The Spanish word bailábamos ("we were dancing, we used to dance") is in the imperfect tense.

3

: not enforceable by law : enforceable only under certain conditions

That obligation would be a constitutional duty and a political obligation, but not a legally enforceable one. In legal terms, it would be described as a "duty of imperfect obligation."

—Anne Twomey

imperfectly

(ˌ)im-ˈpər-fik(t)-lē 

adverb

imperfectness

(ˌ)im-ˈpər-fik(t)-nəs 

noun

Synonyms of imperfect

• defective
• bad
• flawed

Examples of imperfect in a Sentence

It's an imperfect solution to a difficult problem.

He had an imperfect understanding of the task.

In “He was singing when I came in,” “was singing” is in the imperfect tense.

Recent Examples on the Web

Any robot player also has to factor in time lags from motors, cameras, voltage fluctuations, mechanical vibrations, and imperfect puck tracking. —Christopher McFadden, Interesting Engineering, 7 June 2026

An imperfect career, yes, but also one of profound resilience. —Los Angeles Times, 7 June 2026

Price indices are imperfect instruments, and their imperfections cannot be eliminated through methodological ingenuity alone. —James Broughel, Forbes.com, 6 June 2026

The first two are understandable, although travel restrictions and an evacuation ward are inevitably imperfect. —Tom Frieden, STAT, 6 June 2026

Word History

Etymology

alteration of Middle English imparfit, from Latin imperfectus, from in- + perfectus perfect

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing imperfect

• imperfect fungus
• the imperfect

Kids Definition

imperfect

1 of 2 adjective

im·​per·​fect (ˈ)im-ˈpər-fikt 

1

: not perfect:

a

: defective

imperfect clothing

b

: having stamens or pistils but not being a flower with both

2

: of, relating to, or being a verb tense used to express a continuing state or an incomplete action especially in the past

imperfectly

-fik-(t)lē 

adverb

imperfect

2 of 2 noun

: the imperfect tense of a verb or a verb in this tense

Legal Definition

imperfect

adjective

im·​per·​fect

: not perfect or complete: as

a

: not enforceable : enforceable only under certain conditions

an imperfect obligation

b

: lacking an element otherwise required by law compare perfect