乞食は三日もやれば止められない。

English Translation

Once a beggar, always a beggar.

I prefer 物乞い (pron. ものごい) over 乞食 for a better collocation.

  • 乞食 is a “beggar” (person who begs).
  • 物乞い is “begging” (gerund or verb noun).

やる means “to do”. We don’t usually say 乞食をやる (i.e. “to do a beggar” also sounds unnatural in English) but 物乞いをやる/する (to do begging for food/money).