Green’s Dictionary of Slang

kitten n.

1. [19C] a pint or half-pint pot [i.e. a small cat n.4 ].

2. [1900s] (US Und.) the junior member of a gang, used to check places susceptible to a robbery, etc. [dimin. of SE cat, but note cat n.1 (3a)].

3. a young woman [dimin. of SE cat but also play on cat n.1 (1c)].

(a) [1900s] an attractive young woman.

(b) [1920s+] (US black) a young, inexperienced girl.

(c) [1930s+] an affectionate term of address to one’s girlfriend or child.

(d) [1940s+] (US black) a girlfriend [a jazz-era coinage, plays on cat n.5 (1)].

4. [1990s+] the vagina [var. on cat n.1 (2a)].

SE in slang uses

In compounds

In phrases

have kittens (v.) (also cast a kitten, get kittens, ...zebras, have a kitty, ...kittens in the granary, ...pups) [the nervousness of a pregnant cat]

[20C+] to worry to excess, to throw a fit, to succumb to one’s emotions, to lose one’s temper, often through worry or fear.

real kittens (n.)

[1900s] (US) something or someone exceptional.