1. 偶然的：cause 原因 | causeless 偶然的 | causer 引起者

2. 无原因的：犯罪原因论 causationism of crime | 因果 cause and effect | 无原因的 causeless

3. 无显著原因的：无显性组合nulliplex | 无显著原因的causeless | 无现金cashless

4. 无显著原因的, 偶然的：cause tensor || 张量起因 | causeless || 无显著原因的, 偶然的 | causer || 引起者, 引起因素

adj

1. having no cause or apparent cause

    e.g. a causeless miracle
           fortuitous encounters--strange accidents of fortune
           we cannot regard artistic invention as...uncaused and unrelated to the times

    Synonym: fortuitousuncaused

2. having no justifying cause or reason

    e.g. a senseless, causeless murder
           a causeless war that never had an aim
           an apparently arbitrary and reasonless change

    Synonym: reasonless