Definitions:
having all the required or desirable elements, qualities, or characteristics; as good as it is possible to be

absolute; complete (used for emphasis)

(of a number) equal to the sum of its positive divisors, e.g. the number 6, whose divisors (1, 2, 3) also add up to 6.

(of a tense) denoting a completed action or a state or habitual action which began in the past. the perfect tense is formed in english with have or has and the past participle, as in they have eaten and they have been eating (present perfect), they had eaten (past perfect), and they will have eaten (future perfect).

(of a flower) having both stamens and carpels present and functional.

make (something) completely free from faults or defects; make as good as possible

the perfect tense.