know one's stuff

English

Verb

know one's stuff (third-person singular simple present knows one's stuff, present participle knowing one's stuff, simple past knew one's stuff, past participle known one's stuff)

1. (intransitive, informal) To be knowledgeable about and competent at a particular subject or task.

   Joe really knows his stuff when it comes to baseball.

   • 2020, Emmet Sweeney, The Theban Empire, volume 3, page 176:

     The field of knowledge in which Hori claimed to be an authority was Palestinology. The contents of the missive show that Hori certainly knew his stuff.

Synonyms

• know one's shit (vulgar)
• know one's onions
• know one's way around
• know the drill
• know the score
• know which end is up

Antonyms

• See know one's ass from a hole in the ground

Translations

be generally experienced and knowledgeable

• Danish: kende sin vej rundt
• Polish: znać się na czymś impf
• Turkish: avucunun içi gibi bilmek (tr)

knowledgeable in a particular field

• Danish: kunne sit kram, være velindsat
• Finnish: osata hommansa
• French: toucher sa bille (fr)
• German: sich gut auskennen, gut Bescheid wissen
• Italian: sapere il fatto proprio

Further reading

• “know one's stuff”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.