What does "sarcastic" mean?

1. (mocking speech) using words that mean the opposite of what you really think to make fun of someone or something. 2. (personality trait) describing a person who often makes jokes that mock others or uses sharp irony.

Is it correct to say "He said a sarcastic joke about my hair."?

No — say "He made a sarcastic comment about my hair.". While 'sarcastic joke' is possible, 'sarcastic comment' or 'sarcastic remark' are much more common collocations.

sarcastic

adj.

US //sɑɹˈkæstɪk// UK //sɑːkˈɑːstɪk// sar·cas·tic

1 mocking speech (adj.)
B2 Upper Intermediate

using words that mean the opposite of what you really think to make fun of someone or something.

containing or expressing sarcasm; using irony to mock or convey contempt.

Example

"Oh, great job," he said in a sarcastic voice after I dropped the tray.

Example

The critic's review was filled with sarcastic observations about the director's lack of originality and the lead actor's wooden performance.
- sincere
- earnest
Pitfall

He said a sarcastic joke about my hair.

He made a sarcastic comment about my hair.

While 'sarcastic joke' is possible, 'sarcastic comment' or 'sarcastic remark' are much more common collocations.
2 personality trait (adj.)
B2 Upper Intermediate

describing a person who often makes jokes that mock others or uses sharp irony.

habitually using sarcasm as a primary mode of communication or humour.

Example

She is very sarcastic, so it is sometimes hard to tell if she is being serious.

Example

Known for his sarcastic wit, the comedian often alienated audience members who were unprepared for his biting social commentary.
- snarky
- cynical
- polite
- straightforward

Origin

Either from sarcasm + -astic or from French sarcastique, from French sarcasme, from Late Latin sarcasmus, ultimately from Ancient Greek σαρκασμός (sarkasmós, “sarcasm”), itself from Ancient Greek σάρξ (sárx, literally “meat, flesh”).

Word family

Adjectivesarcastic
Adverbsarcastically