1. （短暂的）情事;露水情缘
If two people have a brief romantic relationship, you can say that they have a dalliance with each other, especially if they do not take it seriously.

2. 短暂参与;短暂接触
Someone's dalliance with something is a brief involvement with it.

1. playful behavior intended to arouse sexual interest

Synonym: flirtflirtingflirtationcoquetrytoying

2. the deliberate act of delaying and playing instead of working

Synonym: dawdlingtrifling