From the Strong's...
5046. teleios
having reached its end, i.e. complete, by ext. perfect
Original Word: τέλειος, α, ον
Part of Speech: Adjective
Transliteration: teleios
Phonetic Spelling: (tel'-i-os)
Short Definition: perfect, full-grown
Definition: perfect, (a) complete in all its parts, (b) full grown, of full age, (c) specially of the completeness of Christian character.
Cognate: 5046 téleios (an adjective, derived from 5056 /télos, "consummated goal") – mature (consummated) from going through the necessary stages to reach the end-goal, i.e. developed into a consummating completion by fulfilling the necessary process (spiritual journey). See 5056 (telos).
[This root (tel-) means "reaching the end (aim)." It is well-illustrated with the old pirate's telescope, unfolding (extending out) one stage at a time to function at full-strength (capacity effectiveness).]
Word Origin
from telos
Definition
having reached its end, i.e. complete, by ext. perfect
NASB Word Usage
complete (2), mature (4), more perfect (1), perfect (12).