card-carrying, adj. — Green’s Dictionary of Slang

card-carrying adj.

[the orig. application of the phr. to Communists, who carried their Party card]

(US) genuine, dependable, the ‘real thing’.

1964		L. Hansberry Sign in Sidney Brustein’s Window in Three Negro Plays (1969 I i: Do you know how one can always, infallibly, no matter what, tell a card-carrying phony?
1977		H. Ellison Flop Sweat in Shatterday (1982) 63: A certifiable nut-case, a card-carrying whacko.
1986		C. Hiaasen Tourist Season (1987) 61: He’s also a card-carrying flake.
1999		Eve. Standard 28 May 35: He is no ‘card-carrying member’ of the gay community.
2004		C. Hiaasen Skinny Dip 314: Lady, your husband is a card-carrying shitwad.