1foul 
/ˈfawəl/ adjective
foul·er; foul·est /ˈfawəl/ adjective [or more foul; most foul] 1 : very unpleasant to taste or smell
▪ the foul odor of rotten eggs ▪ foul breath/air ▪ The medicine left a foul taste in my mouth. ▪ a foul-smelling chemical 2 : morally bad : very evil
▪ a foul crime 3 : very bad or unpleasant
▪ He was in a foul [=angry] mood. ▪ The weather has been foul all week. ▪ They do their job in fair weather and foul. [=in good weather and bad weather] 4 : indecent and offensive
▪ foul [=dirty] language ▪ She has a foul mouth. [=she uses foul language; she speaks in an indecent and offensive way] — see also foul-mouthed 5 : very unfair : not morally or socially acceptable
▪ He's determined to get what he wants, whether by fair means or foul. — see also foul play 6 baseball : outside the area between the foul lines
▪ foul territory ▪ a foul grounder ◊A foul ball is a batted ball that lands in the area outside the foul lines. — compare 1fair 8
▪ the foul odor of rotten eggs ▪ foul breath/air ▪ The medicine left a foul taste in my mouth. ▪ a foul-smelling chemical
▪ a foul crime
▪ He was in a foul [=angry] mood. ▪ The weather has been foul all week. ▪ They do their job in fair weather and foul. [=in good weather and bad weather]
▪ foul [=dirty] language ▪ She has a foul mouth. [=she uses foul language; she speaks in an indecent and offensive way] — see also foul-mouthed
▪ He's determined to get what he wants, whether by fair means or foul. — see also foul play
▪ foul territory ▪ a foul grounder ◊A foul ball is a batted ball that lands in the area outside the foul lines. — compare 1fair 8
fall foul of
: to get into trouble because of (the law, a rule, etc.)
▪ After leaving school she fell foul of the law. [=she got into trouble with the law; she was arrested for committing a crime] ▪ companies that fall foul of labor laws
▪ After leaving school she fell foul of the law. [=she got into trouble with the law; she was arrested for committing a crime] ▪ companies that fall foul of labor laws
— foul·ly adverb
▪ He was foully [=brutally] murdered.
▪ He was foully [=brutally] murdered.
— foul·ness noun [noncount]
▪ the foulness of the water/air/odor ▪ the foulness of his crimes/mood
▪ the foulness of the water/air/odor ▪ the foulness of his crimes/mood
