sneaking

sneaking /ˈsniːkɪŋ/ adjective
sneaking
/ˈsniːkɪŋ/
adjective
Britannica Dictionary definition of SNEAKING
always used before a noun
1 
: behaving in a secret and dishonest manner
2 
: not openly expressed — usually + for
3 
◊ If you have a sneaking feeling/suspicion, you think that something might be true or might happen even though you have no definite reason to think so.