Foul-mouth is a term used to describe someone who speaks in an offensive or vulgar manner. The two crossword solutions for this term are 'curser' and 'cusser, ' both of which refer to someone who uses profanity or other offensive language. Curser is derived from the Latin word 'cursus, ' meaning 'to curse, ' while cusser is derived from the Middle English word 'cusse, ' meaning 'to swear.' Both terms are used to describe someone who speaks in a crude or offensive manner.