late 14c., singularli, "exclusively, alone, solely; uniquely; individually; in an unusual way, especially," from singular + -ly (2).
Entries linking to singularly
singular adj.
mid-14c., singuler, "alone, apart; being a unit; special, unsurpassed," from Old French singuler "personal, particular; distinctive; singular in number" (12c., Modern French singulier) or directly from Latin singularis "single, solitary, one by one, one at a time; peculiar, remarkable," from singulus "one, one to each, individual, separate" (see single (adj.)).
In grammar, "relating to one person or thing," late 14c. The meaning "remarkably good, unusual, rare, separated from others (by excellence), uncommon" is from c. 1400 in English; this also was a frequent meaning of Latin singularis. The meaning "out of the usual course, somewhat strange" (shading toward "eccentric, peculiar") is by 1680s.
-ly 2
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.