past tense and past participle of string (v.). From 1680s as an adjective; in reference to nerves, feelings, etc., from 1840. Strung out is from 1902 as "spread out in a line;" slang meaning "addicted" is recorded from 1959.
keys strung on a red cord
strudel
struggle
Struldbrug
strum
strumpet
strung
strut
struthious
Struwwelpeter
strychnine
Stuart