be/get out of practice
US /biː/ɡɛt aʊt əv ˈpræk.tɪs/
UK /biː/ɡɛt aʊt əv ˈpræk.tɪs/

1.
to be or become less good at doing something than you were, because you have not done it for a long time
:
•
I used to play the piano really well, but I'm a bit out of practice now.
•
After not driving for a year, I really got out of practice.