imperfect

American  

[im-pur-fikt] / ɪmˈpɜr fɪkt /

adjective

1. relating to or characterized by defects or weaknesses.

   With my imperfect vision I couldn’t make out the street name.

   Synonyms:

   faulty, defective

2. not perfect; lacking completeness.

   Human knowledge on all subjects is imperfect.

   Synonyms:

   immature, underdeveloped, incomplete

   Antonyms:

   complete

3. Grammar. designating a verb aspect, tense, or other verb category used to express an action or state still in process at some point of reference in time, especially in the past.

4. Law. being without legal effect or support; unenforceable.

5. Botany. (of a flower) diclinous.

6. Music. of or relating to the interval of a major or minor third or sixth.

---

noun

Grammar.

1. 1. in some languages, a verb aspect, tense, or other verb category used to express an action or state still in process at some point of reference in time, especially in the past.

   2. an instance or form of a specific verb in such an aspect, tense, or construction, such as Latin portābam “I was carrying.”

imperfect British  

/ ɪmˈpɜːfɪkt /

adjective

1. exhibiting or characterized by faults, mistakes, etc; defective

2. not complete or finished; deficient

3. botany

   1. (of flowers) lacking functional stamens or pistils

   2. (of fungi) not undergoing sexual reproduction

4. grammar denoting a tense of verbs used most commonly in describing continuous or repeated past actions or events, as for example was walking as opposed to walked

5. law (of a trust, an obligation, etc) lacking some necessary formality to make effective or binding; incomplete; legally unenforceable See also executory

6. music

   1. (of a cadence) proceeding to the dominant from the tonic, subdominant, or any chord other than the dominant

   2. of or relating to all intervals other than the fourth, fifth, and octave Compare perfect

---

noun

1. grammar

   1. the imperfect tense

   2. a verb in this tense

Other Word Forms

• imperfectness
  noun
• imperfectly
  adverb

Etymology

Origin of imperfect

First recorded in 1300–50; from Latin imperfectus “unfinished”; equivalent to im- ² + perfect; replacing Middle English imparfit, from Middle French imparfait, from Latin, as above

Explanation

Something imperfect has flaws, errors, or problems. Imperfect is the opposite of perfect. Imperfect comes from the Latin word imperfectus, meaning “incomplete." If you have an imperfect knowledge of French, you might be able to order a coffee in Paris but not chat with the waiter. Something imperfect is unfinished or damaged in some way. Scuffed silver shoes are imperfect. A great baseball player who makes one error is imperfect. Getting 100 on a test is perfect, but getting a 98 is imperfect. If it’s lacking something, it’s imperfect.

Example Sentences

See Examples For:

imperfect

While the paper acknowledges that chain-of-thought monitoring is imperfect, and may be fragile, the authors wrote that the technique shows promise for detecting AI misbehavior, and the industry should study ways to preserve it.

From The Wall Street Journal ● Oct. 7, 2026

Your imperfect, wonderful life was always a shared endeavor.

From MarketWatch ● Oct. 1, 2026

An ode to imperfect fruit: Tangerines that are a breeze to peel.

From Slate ● Sep. 23, 2026

The system’s long-running ambition to admit students of all backgrounds has had, to say the least, an imperfect success rate.

From Los Angeles Times ● Sep. 22, 2026

When he realized that his observatory shook slightly in the wind, making his measurements imperfect, he moved his instruments into underground bunkers.

From "The Invention of Science" by David Wootton

Related Words

• immature
• incomplete
• inexact
• rudimentary
• sketchy
• warped