Surreptitious
Part of speech: adjective
Definition: stealthy, furtive, well hidden, covert (especially movements)
Sneak
Part of speech: noun
Definition: A mean, sneaking fellow., A ball bowled so as to roll along the ground; a daisy-cutter
Part of speech: verb
Definition: To creep or steal (away or about) privately; to come or go meanly, as a person afraid or ashamed to be seen; as, to sneak away from company.To hide, especially in a mean or cowardly manner.
Example sentence: We have little bags we pack specifically for touch-up makeup if you're chosen for the top 16. I knew I had to sneak in my banana because nothing calms my nerves like it! I don't know if it's the potassium, but I need it before I get on stage because it always calms me down.