perfectible

Concise Oxford English Dictionary © 2008 Oxford University Press:
perfect

▶adjective /ˈpəːfɪkt/ 

• 1 having all the required elements, qualities, or characteristics.

• 2 free from any flaw; faultless.

• 3 complete; absolute: it made perfect sense.

• 4 Mathematics (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.

• 5 Grammar (of a tense) denoting a completed action or a state or habitual action which began in the past, formed in English with have or has and the past participle, as in they have eaten.

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

  ■ denoting the stage or state of a fungus in which the sexually produced spores are formed.

• 7 Entomology (of an insect) fully adult and (typically) winged.

▶verb /pəˈfɛkt/ 

• 1 make perfect.

• 2 bring to completion.

▶noun /ˈpəːfɪkt/ (the perfect) Grammar the perfect tense.

– derivatives
perfecter noun,
perfectibility noun,
perfectible adjective,
perfectly adverb,
perfectness noun.

– origin ME: from OFr. perfet, from L. perfectus, perficere ‘complete’.