nasty

¹ American  

[nas-tee] / ˈnæs ti /

adjective

nastier, nastiest

1. physically filthy; disgustingly unclean.

   a nasty pigsty of a room.

   Synonyms:

   grimy, foul, dirty

   Antonyms:

   unstained, spotless, immaculate, clean

2. offensive to taste or smell; nauseating.

   This ointment is really nasty—couldn't they make it smell less vile?

   Synonyms:

   ugly, catty, bitchy, malevolent, malicious, mean, repellent, repulsive, sickening

3. offensive; objectionable.

   a nasty habit.

4. vicious, spiteful, or unkind.

   a nasty dog;

   a nasty rumor.

5. bad or hard to deal with, encounter, undergo, etc.; dangerous; serious: a nasty accident.

   a nasty cut;

   a nasty accident.

6. very unpleasant or disagreeable.

   nasty weather.

   Synonyms:

   inclement, stormy

7. morally filthy; obscene; indecent.

   a nasty word.

   Synonyms:

   smutty

8. Slang. formidable: a young pitcher with a nasty slider.

   the raw, nasty power of this engine;

   a young pitcher with a nasty slider.

---

noun

plural

nasties

1. Informal. a nasty person or thing.

-nasty ² American  

1. a combining form with the meaning “nastic pressure,” of the kind or in the direction specified by the initial element.

   hyponasty.

---

nasty ¹ British  

/ ˈnɑːstɪ /

adjective

1. unpleasant, offensive, or repugnant

2. (of an experience, condition, etc) unpleasant, dangerous, or painful

   a nasty wound

3. spiteful, abusive, or ill-natured

4. obscene or indecent

5. informal a cruel or mean person

---

noun

1. an offensive or unpleasant person or thing

   a video nasty

-nasty ² British  

combining form

1. indicating a nastic movement to a certain stimulus

   nyctinasty

---

Other Word Forms

• -nastic combining form
• nastily adverb
• nastiness noun

Etymology

Origin of nasty¹

First recorded in 1350–1400; Middle English, further origin unknown

Origin of -nasty²

< Greek nast ( ós ) pressed close ( see nastic) + -y ³

Explanation

Something nasty is filthy, foul, dirty, or awful. Nasty isn't a word for anything nice. The main meaning of nasty is for things that are unpleasant and very gross. If someone throws up in class, at least one student will probably say, "That's nasty!" The smell of a bathroom is nasty. A song full of dirty words is nasty in a different way. Nasty can also mean "extremely." In football, a vicious hit can be called a nasty hit. A mean person is a nasty person too.

Example Sentences

A vaccine during pregnancy which protects newborns against nasty chest infections is cutting hospital admissions of babies by more than 80%, UK health officials say.

From BBC • Apr. 17, 2026

That segment of the show largely stripped out the guitars to focus on clubby techno and nasty slashes of synth noise.

From Los Angeles Times • Apr. 12, 2026

Laing laughs as he recalls one nasty comment that stuck.

From BBC • Apr. 4, 2026

As Mr. Clark tells us, an allegation against the pastors was set in motion in 1835 by Count Finck von Finckenstein, a nasty moral scold and the villain of the story.

From The Wall Street Journal • Mar. 27, 2026

Another smelled like a pile of wet rope encrusted with seaweed and left to rot in the sun, and a nasty, fishy aroma it was.

From "The Long-Lost Home" by Maryrose Wood

Related Words

• awful
• dirty
• fierce
• horrible
• icky
• murderous
• noxious
• obnoxious
• ornery
• outrageous
• rough
• tough
• unpleasant
• vile
• vulgar