Absence of Motive
Nouns
- absence of motive, aimlessness
- caprice etc. Caprice
- chance etc. (absence of design) [Absence of purpose in the succession of events] Chance.
Verbs
- have no motive
- scruple etc. (be unwilling) Unwillingness.
Adjectives
- without rhyme or reason
- aimless, capricious, whimsical etc. (chance) [Absence of purpose in the succession of events] Chance.
Adverbs
- out of mere caprice.