Green’s Dictionary of Slang

come it v.1

1. [late 18C+] to act, to perform, to behave in a certain manner; usu. constr. with an adv.

2. [early–mid-19C] to show off, to boast.

3. [early 19C+] to act aggressively, often with no grounds for so doing.

4. [mid-19C] to impress as a lover.

5. [mid-19C–1910s] to deceive another for one’s own benefit, esp. to avoid an unpleasant task.

6. [1900s–20s] to be cheeky.

In phrases

come it over (v.) (also come it on) [mid-19C+]

1. to compel, to intimidate.

2. (US) to trick, to deceive.

come it strong (v.)

1. [early 19C+] (also go it strong) to act in a challenging, aggressive manner; sometimes intensified by ‘as mustard’.

2. [mid-19C] to act, to practise, to perform one’s part.

3. [mid-19C] to tell lies.

come it with (v.)

[late 19C+] to act in a certain way in order to take advantage (of someone).