sneaking

Acting in a stealthy, furtive way.

Unavowed; secret.

Gradually growing or persistent.

Pertaining to or worthy of a sneak: acting like or characteristic of a sneak; mean; servile; crouching.

Secret or clandestine, and somewhat discreditable; underhand; hence, in a less reprehensible sense, unavowed; not openly or frankly declared.

Marked by cowardly concealment; deficient in openness and courage; underhand; mean; crouching.

Present participle of sneak.

not openly expressed