These words describe things done in concealment so as not to be noticed or found out. Stealthy comes from an Old English word meaning to steal. It suggests the quiet of an animal moving on padded feet, slyly stealing up on its prey or warily making its way past its enemies.

• The scout made a stealthy approach to the enemy position; The escaping prisoner moved with stealthy tread until he was out of earshot of the sleeping guards.

Furtive comes from the Latin word for thief. It suggests the quick, nervous movements of someone who feels guilty or is afraid of getting caught: the furtive manner of an escaped convict; A furtive glance confirmed his fears—he was being followed. Surreptitious comes from Latin roots meaning to snatch secretly. It describes something forbidden that is done or enjoyed on the sly, at an opportune moment when no one is looking: the surr eptitious reading of a friend’s private diary; a dieter’s surreptitious snack.

Clandestine comes from a Latin word meaning in secret. It suggests the wariness of one who hides what he is doing because of the social or political danger of discovery. What is done clandestinely is either illicit or considered to be so, being done under cover because it is frowned on by society or forbidden by those in authority: a clandestine meeting of young lovers; a clandestine meeting to plan a robbery. Where a surreptitious act is done quickly, a clandestine activity may be carried on over a long period of time: a clandestine love affair: a clandestine publication put out by an underground organization.

Sneaky and underhand carry the suggestion of cheating, of unfair dealings and self-serving manipulations behind the scenes. Whereas the other adjectives emphasize the fear of detection, underhand suggests a sly and crafty secrecy practised not for protection but for gain ?stooping to trickery, deceit or fraud for one’s own profit: to win a union ballot by underhand means. Sneaky is more general and less formal than underhand , and emphasizes the deceitful or double-dealing nature of one’s actions more than the selfishness of one’s motives. It suggests a clandestine or roundabout manner concealing an insidious calculation: There was something sneaky and sinister about him, so that you mistrusted him on instinct; the sneaky habit of filching coins from his mother’s purse.