rooty (adj.)

"underground, downward-growing part of a plant," late Old English rōt and in part from a Scandinavian cognate akin to Old Norse rot "root," figuratively "cause, origin," from Proto-Germanic *wrot (source also of Old English wyrt "root, herb, plant," Old High German wurz, German Wurz "a plant," Gothic waurts "a root," with characteristic Scandinavian loss of -w- before -r-), from PIE root *wrād- "branch, root" (source of wort and radical). The usual Old English words for "root" were wyrttruma and wyrtwala.

Figurative use, "source of a quality or condition," is from late 12c. Of the base parts of teeth, hair, etc., from early 13c. Mathematical sense is from 1550s. Philological sense from 1520s. Slang meaning "penis" is recorded from 1846. In African-American vernacular use, "a spell effected by magical properties of roots," by 1935. The sense of "person considered as the source or offspring of a family or clan" is by early 14c., chiefly biblical.

For coveteousnes is the rote of all evylle, which whill some lusted after, they erde from the feyth, and tanglyd themselves with many sorowes. [I Timothy vi in Tyndale, 1526]

To take root is from mid-15c. as "settle in the ground," hence figurative use (by 1530s). Root beer, made from the extracts of various roots (sarsaparilla, sassafras, etc.), is recorded by 1841, American English; root doctor is from 1821. Roots "established ties with a locality or region; one's background or cultural origins" is by 1921.

adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy). Adjectives such as hugy, vasty are artificial words that exist for the sake of poetical metrics.