/ ˈsniːkɪŋ; NAmE / adjective
[ only before noun ] if you have a sneaking feeling for sb or about sth, you do not want to admit it to other people, because you feel embarrassed, or you are not sure that this feeling is right :
She had always had a sneaking affection for him.
I have a sneaking suspicion that she knows more than she's telling us.