1. 无偿的,没有理由的：15. dislocate 使离开原来位置,打乱正常秩序 | 16. gratuitous 无偿的,没有理由的. | 17. debauch 使失落,放荡

2. 免费的：gratitude 感谢的心情 | gratuitous 免费的 | gratuity 赠物

3. 无根据的：gourmet美食家' | gratuitous无根据的a | gratuity赏钱,小费

4. 无偿的,无必要的：Ingenuous 直率的,坦白的 | Gratuitous 无偿的,无必要的 | Stagnant 停滞的,污浊的,愚笨的

1. 无理由的；不必要的；无缘无故的
If you describe something as gratuitous, you mean that it is unnecessary, and often harmful or upsetting.

e.g. There's too much crime and gratuitous violence on TV.
电视里充斥着犯罪和无端的暴力。
e.g. ...his insistence on offering gratuitous advice.
他坚持要提供一些无谓的建议

adj

1. without cause

e.g. a gratuitous insult

2. unnecessary and unwarranted

e.g. a strikers' tent camp...was burned with needless loss of life

Synonym: needlessuncalled-for

3. costing nothing

e.g. complimentary tickets
free admission

Synonym: complimentarycostlessfreegratis(p)