IPA: //ˈsoʊpər//
KK: /ˈsoʊpər/
A person or business that makes or sells soap.
The soaper created a variety of scented soaps for the local market.
The word 'soaper' is derived from 'soap' (from Old English *sāpe*, meaning a substance used for washing) and the suffix '-er' (meaning a person who). A 'soaper' is a person who uses or makes soap.
Think of someone who uses soap to clean — the '-er' indicates a person, so a 'soaper' is simply someone who soaps.