hit on
US /hɪt ɑːn/
UK /hɪt ɑːn/

1.
to make sexual advances toward someone
:
•
He tried to hit on her at the bar.
•
She didn't like it when he started to hit on her.
2.
to suddenly discover or think of something
:
•
I think I've hit on a solution to the problem.
•
They finally hit on a way to make the process more efficient.