sneak/ sniːk /

1.vi.[US] 
to sneak in/out 偷偷溜进/出

2.vt.
to sneak a look at sth 偷看一眼某物

to sneak sb/sth into a place
将某人/某物偷带进一个地方
3.noun [c] [inf] 
(telltale) 告密者