"wantoner" in the adjective sense
1. motiveless, unprovoked, wanton
occurring without motivation or provocation
"motiveless malignity"
"unprovoked and dastardly attack"- F.D.Roosevelt
2. easy, light, loose, promiscuous, sluttish, wanton
casual and unrestrained in sexual behavior
"her easy virtue"
"he was told to avoid loose (or light) women"
"wanton behavior"
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License