also softie, 1863, "silly person," from soft (adj.) + -y (3). Meaning "soft-hearted person" is from 1886; that of "weak, unmanly or effeminate man" is from 1895. The Mister Softee soft ice-cream operation began in Philadelphia, U.S., in 1956.
Old English softe, earlier sefte, "gentle, mild-natured; easeful, comfortable, calm, undisturbed; luxurious," from West Germanic *samfti, from Proto-Germanic *samftijaz "level, even, smooth, gentle, soft" (source also of Old Saxon safti, Old High German semfti, German sanft; and from a variant form with -ch- for -f-, Middle Dutch sachte, Dutch zacht, German sacht), from root *som- "fitting, agreeable."
From c. 1200 of material things, "not stiff, not coarse, fine; yielding to weight." From late 14c. of wind, rain, etc. Of sounds, "quiet, not loud," from early 13c. Of words, "mild, restrained; courteous" mid-14c. From late 14c. as "indulgent," also "physically feeble; easily overcome, lacking manly courage." From 1755 of water ("relatively free from mineral salts"), from 1789 of coal. Meaning "foolish, simple, silly" is attested from 1620s; earlier "easily moved or swayed; soft-hearted, sympathetic; docile" (early 13c.). In reference to drinks, "non-alcoholic" from 1880. As an adverb, Old English softe "gently;" late 13c. as "quietly." As an interjection from 1540s.
Soft landing is from 1958 and the U.S. space program. Adjective soft-core (in reference to pornography) is from 1966 (see hardcore). Soft rock as a music style is attested from 1969. Soft sell is from 1955. Soft-shoe as a dancing style is attested from 1927. Soft-boiled is from 1757 of eggs; of persons, ideas, etc., 1930 (compare half-baked). Soft-focus (adj.) of camera shots is from 1917. The softer sex "women collectively" is from 1640s.
suffix in pet proper names (such as Johnny, Kitty), first recorded in Scottish c. 1400; according to OED it became frequent in English 15c.-16c. Extension to surnames seems to date from c. 1940. Use with common nouns seems to have begun in Scottish with laddie (1546) and become popular in English due to Burns' poems, but the same formation appears to be represented much earlier in baby and puppy.