to do something that you know involves a risk:
I wasn't sure if I'd got quite enough petrol to get me home, but I decided to chance it.
We decided not to chance our luck in the storm.
She'd never played before, but she was ready to chance her arm (=take a risk by doing something which may fail).
chance doing something
I decided to stay where I was. I couldn't chance being seen.
2 [intransitive] literary
to happen in a way which is not expected and not planned
chance to do something
She chanced to be passing when I came out of the house.
It chanced that we both went to Paris that year.
chance on/upon/across somebody/somethingphrasal verb
Henry chanced upon some valuable coins in the attic.