Green’s Dictionary of Slang

come on v.1

[ext. of come v.3 ; var. on come over v.2 /come the... v.]

1. [mid-19C+] (orig. US) to seem, to appear, to behave; always modified, usu. by an adj. used adverbially, e.g. come on tough, come on nasty etc.

2. see come on strong

In phrases

come on like a test pilot (v.) [the test pilot, as a figure of technologically sophisticated derring-do, had a higher profile then than now]

[1940s] (US black/Harlem) to act in a speedy, efficient manner.

come on strong (v.) (also come on, come strong)

1. [20C+] to speak aggressively, forcefully; to make one’s presence and opinions felt; used both positively and negatively, the latter often as come on too strong.

2. [1950s+] to be seductive.