sledge n.1

early 14c., sledde, "a dragged vehicle used for transport of heavy goods over hard ground or ice," from Middle Dutch sledde "sled," from Proto-Germanic *slid- (source also of Old Saxon slido, Old Norse sleði, Danish slæde, Swedish släde, Old High German slito, German Schlitten "sledge"), from the same root as Old English slidan (see slide (v.)). Not found in Old English.

In reference to a sleigh used for travel or recreation, it is attested from 1580s, now mainly American English. In reference to a pair of runners connected by a framework with a light platform or seat, used for pleasure coasting, by 1873.

Middle English slēn, "strike, beat, strike so as to kill, commit murder," from Old English slean "to smite, strike, beat," also "to kill with a weapon, slaughter" (class VI strong verb; past tense sloh, slog, past participle slagen), from Proto-Germanic *slahanan "to hit" (source also of Old Norse and Old Frisian sla, Danish slaa, Middle Dutch slaen, Dutch slaan, Old High German slahan, German schlagen, Gothic slahan "to strike"). The Germanic words are said to be from PIE root *slak- "to strike" (source also of Middle Irish past participle slactha "struck," slacc "sword"), but, given certain phonetic difficulties and that the only cognates are Celtic, Boutkan says the evidences "point to a North European substratum word."

The verb slēn displays many nondialectal stem variants because of phonological changes and analogical influences both within its own paradigm and from other strong verbs. [Middle English Compendium]

Modern German cognate schlagen maintains the original sense of "to strike."

It is attested by late 12c. as "destroy, put an end to." The meaning "overwhelm with delight" (mid-14c.) preserves one of the wide range of meanings the word once had, including, in Old English, "stamp (coins); forge (weapons); throw, cast; pitch (a tent), to sting (of a snake); to dash, rush, come quickly; play (the harp); gain by conquest."

"large hammer," formerly used chiefly by blacksmiths, late 15c., from sledge (n.1) + hammer (n.). As a verb, from 1834. Old English had slegebytel "hammer," with beetle (n.2).