"small, secluded restaurant, etc.," 1929, from hide (v.1) + away. Earlier it meant "a fugitive person" (1871). Compare runaway, stowaway.
Entries linking to hideaway
hide v.1
Old English hydan (transitive and intransitive) "to hide, conceal; preserve; hide oneself; bury a corpse," from West Germanic *hudjan (source also of Middle Dutch, Middle Low German huden), from suffixed form of PIE *keudh- (source also of Greek keuthein "to hide, conceal"), from root *(s)keu- "to cover, conceal."
away adv.
Middle English awei, from late Old English aweg, earlier on weg "on from this (that) place;" see a- (1) + way (n.).
The meaning "from one's own or accustomed place" is from c. 1300; that of "from one state or condition to another" is from mid-14c.; that of "from one's possession (give away, throw away) is from c. 1400. Colloquial use for "without delay" (fire away, also right away) is from the earlier sense of "onward in time" (16c.). The meaning "at such a distance" (a mile away) is by 1712. Intensive use (as in away back) is American English, attested by 1818. Of sporting events played at the other team's field or court, by 1893.