expression, godan verb (-ku)
cut corners; slack off; hold back
Idiomatic expression meaning to do something carelessly or with less effort than usual, or to go easy on someone in a competitive situation. The nuance depends on context: it can be negative (shoddy work) or neutral (not giving full effort against a weaker opponent).
仕事で手を抜くと、あとで問題になるよ。
If you cut corners at work, it'll cause problems later.
Since my opponent was a beginner, I held back a little.