clumsy: [16] When clumsy first appeared on the scene around 1600, both it and the presumably related but now obsolete clumse were used not only for ‘awkward’ but also for ‘numb with cold’. This, and the fact that the word’s nearest apparent relatives are Scandinavian (such as Swedish dialect klumsig ‘numb, clumsy’), suggests that the notion originally contained in them was of being torpid from cold – so cold that one is sluggish and cannot coordinate one’s actions.
clumsy (adj.)
1590s, "acting as if benumbed," alteration of Middle English clumsid "numb with cold" (14c.), past participle of clumsen "to benumb, stiffen or paralyze with cold or fear," from a Scandinavian source akin to Old Norse klumsa "make speechless, palsy; prevent from speaking," intensive of kluma "to make motionless." For insertion of -s-, see flimsy.
Not in general use until 18c., with senses "manifesting awkwardness; so made as to be unwieldy." Related: Clumsily; clumsiness. Compare Swedish dialectal klummsen "benumbed with cold," Norwegian klumsad (past participle) "speechless, palsied by a spasm or by fear or witchery;" German verklammen "grow stiff or numb with cold." Also compare clumse (n.) "a stupid fellow."