1: πρῶτος
(Strong's #4413 — Adjective — protos — pro'-tos )

is one of two words translated "best" in the AV, but the only one so rendered in the RV. In Luke 15:22 "the best (robe)" is, lit., "the first (robe)," i.e., chief, principal, first in rank or quality. See BEFORE , BEGINNING , CHIEF , FIRST , FORMER.

2: μείζων
(Strong's #3187 — Adjective — meizon — mide'-zone )

"greater," is translated "best" in 1—Corinthians 12:31 , "the best gifts," greater, not in quality, but in importance and value. It is the comparative degree of megas, "great;" the superlative, megistos, is used only in 2—Peter 1:4 . See ELDER , GREATER and MORE.