spacy adj.

c. 1300, "extent or area; room" (to do something), a shortening of Old French espace "period of time, distance, interval" (12c.), from Latin spatium "room, area, distance, stretch of time," a word of unknown origin (also source of Spanish espacio, Italian spazio).

From early 14c. as "a place," also "amount or extent of time." From mid-14c. as "distance, interval of space;" from late 14c. as "ground, land, territory; extension in three dimensions; distance between two or more points." From early 15c. as "size, bulk," also "an assigned position." Typographical sense is attested from 1670s (typewriter space-bar is from 1876, earlier space-key, 1860).

Astronomical sense of "stellar depths, immense emptiness between the worlds" is by 1723, perhaps as early as "Paradise Lost" (1667), common from 1890s. Space age is attested from 1946. Many compounds first appeared in science fiction and speculative writing, such as spaceship (1894, "A Journey in Other Worlds," John Jacob Astor); spacecraft (1928, Popular Science); space travel (1931); space station (1936, "Rockets Through Space"); spaceman (1942, Thrilling Wonder Stories). Space race attested from 1959. Space shuttle attested by 1970.

Space isn't remote at all. It's only an hour's drive away if your car could go straight upwards. [Sir Fred Hoyle, London Observer, 1979]

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.

1540s, "to make of a certain extent;" 1680s in typography; 1703 as "to arrange at set intervals," from space (n.). Meaning "to be in a state of drug-induced euphoria" is recorded from 1968. Space cadet "eccentric person disconnected with reality" (often implying an intimacy with hallucinogenic drugs) is a 1960s phrase, probably traceable to 1950s U.S. sci-fi television program "Tom Corbett, Space Cadet," which was watched by many children who dreamed of growing up to be one and succeeded. Related: Spaced; spacing.