5 sentences

1. 他无缘无故地迟到了。

   tā wú yuán wú​gù de chí​dào le.

   He was late for no reason at all.

   Source: Dong Chinese Dictionary

2. 他无故缺席了会议。

   tā wú​gù quē​xí le huì​yì.

   He was absent from the meeting without cause.

   Source: Dong Chinese Dictionary

3. 他因为经常无故旷工被公司解雇了。

   tā yīn​wèi jīng​cháng wú​gù kuàng​gōng bèi gōng​sī jiě​gù le.

   He was fired by the company for frequent absenteeism without reason.

   Source: Dong Chinese Dictionary

4. 他因为在街上无故殴打路人而被警察逮捕了。

   tā yīn​wèi zài jiē shàng wú​gù ōu​dǎ lù​rén ér bèi jǐng​chá dài​bǔ le.

   He was arrested by the police for an unprovoked assault on a passerby in the street.

   Source: Dong Chinese Dictionary

5. 那个暴君生性贪婪且残，常常无故处罚身边的侍从。

   nà​gè bào​jūn shēng​xìng tān​lán qiě cán, cháng​cháng wú​gù chǔ​fá shēn​biān de shì​cóng.

   That tyrant was greedy and cruel by nature, often punishing his attendants for no reason.

   Source: Dong Chinese Dictionary