Welsh drwg

← Proto-Brythonic *drug (inherited)

← Proto-Celtic *drukos (inherited)

← Old Irish droch (cognate)

← Middle Welsh drwc (inherited)

→ Breton drouk (cognate)

→ Welsh drygioni (suffix)

→ Welsh cynddrwg (compound)

→ Welsh drycin (compound)

→ Irish droch- (cognate)

→ Cornish drog (cognate)

→ Scots dreich (compound)

→ Old Irish droch (cognate)