shyly adv.

Middle English shei, "easily frightened or startled," from late Old English sceoh "timid, easily startled," from Proto-Germanic *skeukh(w)az "afraid" (source also of Middle Low German schüwe, Dutch schuw, German scheu "shy;" Old High German sciuhen, German scheuchen "to scare away"). Cognates outside Germanic are uncertain, unless perhaps in Old Church Slavonic shchuti "to hunt, incite." Italian schivare "to avoid," Old French eschiver "to shun" are Germanic loan-words.

The meaning "shrinking from contact with others, difficult of approach because of timidity" is by c. 1600. The meaning "lacking, short of" is from 1895, American English gambling slang. As the last element of a compound (gun-shy, etc.) "frightened, averse, reluctant," by 1849.

common adverbial suffix, forming from adjectives adverbs signifying "in a manner denoted by" the adjective, Middle English, from Old English -lice, from Proto-Germanic *-liko- (cognates: Old Frisian -like, Old Saxon -liko, Dutch -lijk, Old High German -licho, German -lich, Old Norse -liga, Gothic -leiko); see -ly (1). Cognate with lich, and identical with like (adj.).

Weekley notes as "curious" that Germanic uses a word essentially meaning "body" for the adverbial formation, while Romanic uses one meaning "mind" (as in French constamment from Latin constanti mente). The modern English form emerged in late Middle English, probably from influence of Old Norse -liga.