Clammy

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late Middle English: from dialect clam ‘to be sticky or adhere’, of Germanic origin; related to clay.

wiktionary

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From Middle English clam(“viscous, sticky; slimy”) +‎ -y, from Old English clǣman(“to smear, bedaub”). Compare German klamm(“clammy”) and klemmen(“to be stuck, stick”). See also clam.

etymonline

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clammy (adj.)

"soft and sticky," late 14c., probably an extended form of Middle English clam "viscous, sticky, muddy" (mid-14c.), from Old English clæm "mud, sticky clay," from Proto-Germanic *klaimaz "clay" (source also of Flemish klammig, Low German klamig "sticky, damp," Old English clæman "to smear, plaster;" and clay). With -y (2). Related: Clammily; clamminess.