Green’s Dictionary of Slang

1. (US) to stare at; to survey.

1918		in Stars and Stripes 28 June: Have yuh double-o-ed a dame? [HDAS].
1935		A.J. Pollock Und. Speaks 33/2: Double O, to size up a person or place.
1944		Slanguage Dict. Mod. Amer. Sl.
1948		Nation’s Business XXXVI 52: [They] are whisked away to mountain lodges to see winter sports fashions in motion, or bathe in the sun at Palm Springs to double-o spectator and leisure wear.
1955		B. Schulberg On the Waterfront (1964) 143: The church job. Double-o it for Johnny.
1980		A. Pearl Dict. Popular Sl.

2. to doublecross.

1929

C. Coe Hooch! 104: ‘Sooner or later he’ll double-cross you,’ the alderman snapped [...] ‘What d’you mean, double-o me?’.

3. to reject, to deny.

1958

Mad mag. Jan.–Feb. 48: I don’t want to double-O what Brutus gummed.