Green’s Dictionary of Slang

Adele Adder n.

[assonant female proper name + image of the stereotypically untrustworthy snake]

(S.Afr. gay) a homosexual person who is vindictive or bitchy; note mis-defined as an adj. in cit. 2003.

[SA]K. Cage Gayle 52/2: Adele Adder adj. gay person with a reputation for vindictiveness, and of whom one should be wary.