Английский словарь американских идиом - sit tight

{v. phr.}, {informal} To make no move or change; stay where you are. - Often used as a command. * /Sit tight; I'll be ready to go in a few minutes./ * /The doctor said to sit tight until he arrived./ * /The gangsters sat tight in the mountains while the police looked for them./ Compare: STAND PAT.