Beetle
Old English bitula, bitela ‘biter’, from the base of bītan ‘to bite’.
wiktionary
From Middle English bitle, bityl, bytylle, from Old English bitula, bitela, bītel(“beetle”), from Proto-Germanic *bitulaz, *bītilaz(“that which tends to bite, biter, beetle”), equivalent to bite + -le. Cognate with Danish bille(“beetle”), Icelandic bitil, bitul(“a bite, bit”), Faroese bitil(“small piece, bittock”).
From Middle English bitel-brouwed(“ beetle-browed”). Possibly after beetle, from the fact that some beetles have bushy antennae.
From Middle English betel, from Old English bīetel, akin to bēatan(“to beat”).
etymonline
beetle (n.1)
insect of the order Coleoptera, Old English bitela "beetle," apparently originally meaning "little biter, biting insect," from bitel "biting," from Proto-Germanic *bitan, from PIE root *bheid- "to split," with derivatives in Germanic referring to biting.
By normal evolution it would be *bittle, but it seems to have been influenced by beetle (n.2). Sometimes applied to soft insects, as black beetle, an old name for the cockroach. As a nickname for the original Volkswagen car, 1946, translating German Käfer.
beetle (v.)
"project, overhang," apparently a Shakespearean back-formation (in "Hamlet," 1602) from bitelbrouwed "grim-browed, sullen" (mid-14c.), from bitel "sharp-edged, sharp" (c. 1200), probably a compound from Old English *bitol "biting, sharp" (related to bite (v.)), + brow, which in Middle English meant "eyebrow," not "forehead." Meaning "to overhang dangerously" (of cliffs, etc.) is from c. 1600. Related: Beetled; beetling.
beetle (n.2)
"heavy wooden mallet used to drive wedges, pack earth, etc.," Old English bietl "mallet, hammer," from Proto-Germanic *bautilo-z, from *bautan "to beat," from PIE root *bhau- "to strike."
