Main entry: inconstant
Definition: likely to change frequently often without apparent or cogent reason; variable
Usage: inconstant affections; an inconstant lover; swear not by...the inconstant moon- Shakespeare
Antonyms: constant
Definition: steadfast in purpose or devotion or affection
Antonyms: nonvolatile, nonvolatilisable, nonvolatilizable
Definition: not volatilizing readily
Antonyms: true
Definition: consistent with fact or reality; not false