What is the meaning of Imperfect?

Not perfect,

Unisexual: having either male (with stamens) or female (with pistil) flowers, but not with both.

Known or expected to be polyphyletic, as of a form taxon.

Representing a continuing or repeated action.

Lacking some elementary organ that is essential to successful or normal activity.

Something having a minor flaw.

A tense of verbs used in describing a past action that is incomplete or continuous.

to make imperfect

imperfect (not perfect)

imperfect

Source: wiktionary.org