1) Acting furtively 2) Concealed 3) Creeping furtively 4) Kind of suspicion 5) Like some suspicions 6) Not openly expressed 7) Unavowed Found on https://www.crosswordclues.com/clue/sneaking
Sneak'ing adjective Marked by cowardly concealment; deficient in openness and courage; underhand; mean; crouching. -- Sneak'ing*ly , adverb -- Sneak'ing*ness , noun Found on http://www.encyclo.co.uk/webster/S/132