slip
/slɪp/ verb (present participle slipping, past tense and past participle slipped)
FALL [I] › to slide by accident and fall or almost fall: She slipped on the ice and broke her ankle. OUT OF POSITION [I] › to slide out of the correct position: The photo had slipped from the frame. slip away/out/through, etc › to go somewhere quietly or quickly: I'll slip out of the room if I get bored.
slip sth into/through, etc › to put something somewhere quickly or secretly: She slipped the letter into an envelope and sealed it.
GIVE SECRETLY [+ two objects] informal › to give something to someone secretly: I slipped her a five pound note. GET LESS/WORSE [I] › to get less or worse in level or quality: His school grades have slipped recently. let sth slip › to forget that something is a secret and tell someone about it → See also slip your mind