cut someone some slack

Don't cut. . . . غلط نمیشه؟
چون خودش معنی منفی داره

To be understanding of someone's situation , to give someone a break

به کسی سخت نگرفتن،
شرایطشو فهمیدن.

سخت نگرفتن، ( راحتش بذار )
to loosen a tight restriction. In this idiom, cut has the meaning of give.
:Or
allow someone some leeway in their conduct

to be easy on someone. for example:
because it was the last day of the school, the teachers cut us some slack.

به کسی آزادی بیشتر دادن
به پشه باند فرودگاه دادن

عبارت غیر رسمی به معنی سخت نگرفتن به کسی
مثال:
you've been studying since this morning continuously . don't cut yourself some slack
از صبح تاحالا بی وقفه داری درس میخونی. به خودت سخت نگیر