Slope
late 16th century (as a verb): from the obsolete adverb slope, a shortening of aslope. The use of the verb with reference to aimless or unobtrusive movement may be related to lope.
wiktionary
From aslope(adjective, adverb).
etymonline
slope (v.)
1590s, "go in an oblique direction," from earlier adjective meaning "slanting" (c. 1500), probably from Middle English aslope (adv.) "on the incline" (late 15c.), from Old English *aslopen, past participle of aslupan "to slip away," from a- "away" + slupan "to slip" (see sleeve). From 1709 as "to be in a slanting position;" transitive sense "place in a slanting position" is from c. 1600. Related: Sloped; sloping.
slope (n.)
1610s, "inclination," from slope (v.). Meaning "an incline, a slant (of ground)" is from 1620s. Derogatory slang meaning "Oriental person" is attested from 1948.
