unforgivingadjective
/ˌʌn.fəˈɡɪv.ɪŋ//-fɚ-/not willing to forgive people for things they do wrong:
My wife is unforgiving by nature.
unpleasant or difficult to deal with:
The unforgiving seas make search and rescue very difficult.
An unforgiving fabric or item of clothing can make you look fat:
Satin is gorgeous but can be unforgiving and emphasize bulges.