To creep or go stealthily; to come or go while trying to avoid detection, as a person who does not wish to be seen.
He decided to sneak into the kitchen for a second cookie while his mom was on the phone.
To take something stealthily without permission.
I went to sneak a chocolate but my dad caught me.
(ditransitive) To stealthily bring someone something.
She asked me to sneak her a phone next month.
To hide, especially in a mean or cowardly manner.
(with on) To inform an authority of another's misdemeanours.
If you sneak on me I'll bash you!
The act of one who sneaks.
Secret or underhand; not openly avowed.