POSSIBLEST

Adjective

possiblest

(nonstandard) superlative form of possible: most possible

Source: Wiktionary

POSSIBLE

Pos"si*ble, a. Etym: [F., fr. L. possibilis, fr. posse to be able, to have power; potis able, capable + esse to be. See Potent, Am, and cf. Host a landlord.]

Definition: Capable of existing or occurring, or of being conceived or thought of; able to happen; capable of being done; not contrary to the nature of things; -- sometimes used to express extreme improbability; barely able to be, or to come to pass; as, possibly he is honest, as it is possible that Judas meant no wrong. With God all things are possible. Matt. xix. 26.

Syn.

– Practicable; likely. See Practicable.

Source: Webster’s Unabridged Dictionary 1913 Edition