Abbreviation of キャバクラ嬢. Refers specifically to a woman working at a kyabakura (キャバクラ), a type of hostess bar. Casual, modern term.
See also: キャバクラ嬢
She works as a hostess at a kyabakura only on weekends.
あの店のキャバ嬢はみんな美人だ。
All the hostesses at that bar are beautiful.
Abbreviation of キャバクラ嬢 (kyabakura-jō), from キャバクラ (kyabakura, a type of hostess bar) + 嬢 (jō, 'young lady' or 'miss'). The term キャバクラ itself is a blend of キャバレー (kyabarē, 'cabaret') and クラブ (kurabu, 'club').