one-to-one
adjective [ before noun ]
uk/ˌwʌntəˈwʌn/ usused to describe the fact of one thing being worth the same as the second:
The old banknotes were exchanged for the new at a one-to-one rate.
MEETINGS ( US one-on-one)
involving only two people:
one-to-one training
a one-to-one meeting