He has let himself go since he lost his job.

他失业后就不修边幅了。

《牛津词典》

After his divorce, he let himself go to seed.

离婚后，他自暴自弃。

《牛津词典》

Silently, he let himself go into the unknown.

他默默地走进未知的世界。

youdao

In Lycidas Milton doesn't let himself, thank God, go quite so far as he does in this amazing ending to "Damon's Epitaph."

感谢上帝，在《利西达斯》中，弥尔顿做的不像，他在《达蒙的墓志铭》的结尾那样过火“

耶鲁公开课 - 弥尔顿课程节选

Pereda realized that he had grasped his knife, then let himself go.

NEWYORKER: The Insufferable Gaucho

Was his sense of structure a noble refusal to wallow in cheap emotion, or evidence of repression, an inability to let himself go?

ECONOMIST: How Brahms saved music from Wagner

It might be some little youngster that probably just he's like trying to make a name for himself, let's go hit them.

NPR: Terror, Hope on the Streets of Compton, Part 1