c. 1400, earlier sclendre (late 14c.), probably from a French source, often said to be from Old French esclendre "thin, slender," which could be from Old Dutch slinder, but the connections, and even the existence of these words, is doubtful. Related: Slenderly; slenderness.
a slender pole
slender wages
sleeve
sleeveless
*sleg-
sleigh
sleight
slender
slenderize
slept
*sleubh-
sleuth
slew