无缘无故

Explanation: Without any reason. 　　Usage: Joint type; as predicate, attributive; for people 　　Source: Qing Cao Xueqin's "Dream of Red Mansions" 44th back Haohao Er, and from there talking about! White for no reason by a gas! " 　　Examples: His power, strength, pride has made him self-esteem, but in the past these days, - he suffered a winding and difficult. ★ Lao She, "Rickshaw" three Thesaurus:  White-browed red eye, without reason or cause, dispatch troops without just cause Antonym Group:   refuse letting others talk, explain, etc., not waiting for an explanation, forbid barge, not entirely devoid of truth, Let things drift., leave sb. alone, allow sth to become neglected, less organized, etc, There are no waves without wind. There's no smoke without fire., doubt, emerge of itself and perish of itself, acquiescently