To involve oneself in an intrusive or nosy manner into something that is not one's business or responsibility. I wish my neighbors would quit sticking their noses in and just leave us alone!Liam, don't stick your nose into your brother's affairs—he can manage well enough on his own.See also: nose, stick
stick one's nose in
(to something) Go to poke one's nose in(to something).See also: nose, stick