source: [名探偵コナン ハンガーを投げつけられ殺人を決意する女性｜無料GIF画像検索 GIFMAGAZINE 3914397]

1. a reason for doing something, especially one that is hidden or not obvious:

【行動などの】動機, 理由, 誘因; 目的 «for, behind»

e.g. a motive for his murder.

2. (in art, literature, or music) a motif:

＝ motif

e.g. the entire work grows organically from the opening horn motive.

adjective attributive

1. producing physical or mechanical motion:

〖名詞の前で〗原動力となる

e.g. the charge of gas is the motive force for every piston stroke.

2. causing or being the reason for something:

動機となる, 行動を促す

e.g. the motive principle of a writer's work.

motiveless |ˈmōdivləs| adjective

motivelessly |ˈmōdivləslē| adverb

motivelessness noun

late Middle English: from Old French motif (adjective used as a noun), from late Latin motivus, from movere ‘to move’.