Strong
Old English, of Germanic origin; related to Dutch and German streng, also to string.
wiktionary
From Middle English strong, strang, from Old English strong, strang(“strong, powerful, mighty, able; firm, constant, resolute, strenuous, hardy; hard, severe, fierce, stern, strict; bold, brave; valid, assured; effective, producing a great effect, potent; earnest; arduous, violent”), from Proto-Germanic *strangaz(“tight, strict, straight, strong”), from Proto-Indo-European *strengʰ-(“taut, stiff, tight”). Cognate with Scots strang(“strong”), Saterland Frisian strang, West Frisian string(“austere, strict, harsh, severe, stern, stark, tough”), Dutch streng(“strict, severe, tight”), German streng(“strict, severe, austere”), Swedish sträng, strang(“severe, strict, harsh”), Norwegian strang(“strong, harsh, bitter”), Norwegian streng(“strong, hard”), Icelandic strangur(“strict”), Latin stringō(“tighten”).
etymonline
strong (adj.)
Old English strang "physically powerful, powerful in effect; forceful, severe, firm, bold, brave; constant, resolute; arduous, violent," from Proto-Germanic *strangaz (source also of Old Norse strangr "strong," Dutch streng "strict, rigorous," Old High German strang "strong, bold, hard," German streng "strict, rigorous"), possibly from PIE *strenk- "tight, narrow." Originally compared strenger, strengest (compare old/elder/eldest).
Grammatical sense, of noun and verb inflections, is first attested 1841, translating German stark, used in a grammatical sense by Jakob Grimm (the terms strong and weak better fit German inflections). Strong suit (1865) is from card-playing. Strong man "man of great strength" (especially one who displays it professionally) is recorded from 1690s; meaning "dominating man in a political organization" is from 1859.
strong (adv.)
Old English strange "strongly, violently, severely, furiously" (alongside strongly), from the same source as strong (adj.). Going strong (1898) is from racing. To come on strong was originally come it strong (1812).
