motive

nouns

the psychological feature that arouses an organism to action toward a desired goal; the reason for the action; that which gives purpose and direction to behavior
"we did not understand his motivation"; "he acted with the best of motives"
motivation, motive, need
is derived from
motivate
a theme that is repeated or elaborated in a piece of music
motif, motive
a design or figure that consists of recurring shapes or colors, as in architecture or decoration
motif, motive

adjectives

causing or able to cause motion
"a motive force"; "motive power"; "motor energy"
motive, motor
is derived from
motivity
impelling to action
"it may well be that ethical language has primarily a motivative function"- Arthur Pap; "motive pleas"; "motivating arguments"
motivating, motivative, motive