dazed or stupefied because of the influence of narcotic drugs.
2.
dreamily or eerily out of touch with reality or seemingly so; spacey.
Also, spaced.
Origin: 1965–70, Americanism; on the pattern of phrasal verbs with out marking perfectivity; space appar. by assoc. with “outer space” as, metaphorically, a place outside normal consciousness
[speyst-out] 
