無緣無故

no cause, no reason (idiom); completely uncalled for

not to have / no / none / not / to lack / un- / -less

to have no opportunity / no way (of doing sth) / no chance / no connection / not placed (in a competition) / (in pop lyrics) no chance of love, no place to be together etc

cause / reason / karma / fate / predestined affinity / margin / hem / edge / along

without cause or reason

happening / instance / reason / cause / intentional / former / old / friend / therefore / hence / (of people) to die, dead