to leave the person or group of people you are with, without telling them where you are going
Small children tend to wander off if you don't watch them all the time.
phrasewander off wander off to leave the place where you are supposed to be, or the person you are with, without saying where you are going: Oh there you are you naughty boy! How many times has Mummy told you not to wander off like that?Sometimes he just wanders off for days on end - we get frantic, not knowing where he is.
wander off
(from someone or something) Go to wander away (from someone or something).