up to sth
phrasal verb.phrasal verb. to be doing something, especially something secret or bad.
phrasal verb. to be occupied with or engaged in an activity; frequently carries a negative prosody implying mischief, secrecy, or illicit behavior.
What are those kids up to in the garden?
He looks very guilty, so I am sure he is up to something he shouldn't be doing.
The investigators suspected the firm was up to some creative accounting to hide their recent losses from the shareholders.
usually used in questions or with indefinite pronouns like 'something', 'anything', or 'nothing'.
distinguish between the neutral 'What are you up to?' (meaning 'What are you doing?') and the suspicious 'What are you up to?' which implies mischief based on tone and context.
What are you up to do?What are you up to?the phrase functions as a predicate adjective or phrasal verb and does not take an infinitive verb after 'to'.
Last updated April 24, 2026