foul
1. [ verb ] make impure
Synonyms: contaminate pollute
Examples:

"The industrial wastes polluted the lake"

Related terms: dirty infect pollution befoulment pollutant contaminant defiler
2. [ adjective ] violating accepted standards or rules
Synonyms: dirty unsporting unsportsmanlike cheating
Examples:

"a dirty fighter" "used foul means to gain power" "a nasty unsporting serve" "fined for unsportsmanlike behavior"

Related terms: unfair
3. [ adjective ] highly offensive; arousing aversion or disgust
Synonyms: disgusting loathsome repelling skanky loathly repellant repellent revolting distasteful wicked yucky disgustful
Examples:

"a disgusting smell" "distasteful language" "a loathsome disease" "the idea of eating meat is repellent to me" "revolting food" "a wicked stench"

Related terms: offensive
4. [ adjective ] highly offensive; arousing aversion or disgust
Synonyms: disgusting loathsome revolting yucky loathly repellent repellant wicked distasteful disgustful
Examples:

"a disgusting smell" "distasteful language" "a loathsome disease" "the idea of eating meat is repellent to me" "revolting food" "a wicked stench"

Related terms: offensive
5. [ adjective ] offensively malodorous
Synonyms: foul-smelling fetid stinking noisome funky putrid smelly foetid
Examples:

"a putrid smell"

Related terms: malodorous
6. [ verb ] (baseball) hit a foul ball, in baseball
Related terms: hit foul_out baseball
7. [ verb ] become or cause to become obstructed
Synonyms: clog choke_off back_up congest choke clog_up
Examples:

"The leaves clog our drains in the Fall" "The water pipe is backed up"

Related terms: unclog obstruct stuff silt_up gum_up crap_up congestion
8. [ adjective ] (nautical) especially of a ship's lines etc
Synonyms: fouled afoul
Examples:

"with its sails afoul" "a foul anchor"

Related terms: tangled
9. [ verb ] spot, stain, or pollute
Synonyms: defile maculate befoul
Examples:

"The townspeople defiled the river by emptying raw sewage into it"

Related terms: dishonor macule defiler befoulment
10. [ adjective ] (sexuality) characterized by obscenity
Synonyms: nasty smutty filthy
Examples:

"had a filthy mouth" "foul language" "smutty jokes"

Related terms: dirty
11. [ adjective ] disgustingly dirty; filled or smeared with offensive matter
Synonyms: filthy nasty
Examples:

"as filthy as a pigsty" "a foul pond" "a nasty pigsty of a room"

Related terms: dirty
12. [ verb ] become foul or dirty
Related terms: change
13. [ adjective ] (informal) thoroughly unpleasant
Synonyms: vile nasty filthy
Examples:

"filthy (or foul or nasty or vile) weather we're having"

Related terms: colloquialism inclement
14. [ adjective ] (of a baseball) not hit between the foul lines
Related terms: fair baseball out-of-bounds out-of-bounds
15. [ adjective ] (of a manuscript) defaced with changes
Synonyms: marked-up dirty
Examples:

"foul (or dirty) copy"

Related terms: illegible
16. [ verb ] (games) commit a foul; break the rules
Related terms: play hack hack
17. [ noun ] (sports) an act that violates of the rules of the sport
Related terms: violation technical personal_foul sport
18. [ verb ] make foul
Examples:

"foul the water"

Related terms: dirty
19. [ noun ] (in baseball) a ball struck with the bat so that it does not stay between the lines (the foul lines) that define the width of the playing field
Synonyms: foul_ball
Related terms: fair_ball contact baseball baseball
Similar spelling:   foully
  fowl
  fool
  foil
  foal
  Fowle
  folly
  folio
  folie
  Foley
  follow