Other forms: two-times
To two-time is to carry on with two partners at once. Two-time a partner.
It is American in origin and now understood everywhere. To two-time somebody is not the same as two-time, meaning twice, which is a different word entirely.
1verbtwo-timeTo carry on with two partners at once.
“He two-timed both of them for a year and lost both.”
two-time is an action.