to be romantically or sexually involved with someone, usually for a short time, without really loving that person

It's cruel the way she just dallies with his affections. 她那样玩弄他的感情真是太残忍了。

to consider or imagine an idea, subject, or plan, but not in a serious way

He had occasionally dallied with the idea of starting his own business, but he had never actually done anything about it. 他偶尔也曾幻想过自己去开个公司，但却从未真正付诸行动。