play up

verb
RareNot in standard dictionaries
1

Used other than figuratively or idiomatically: see play, up.

2

To misbehave.

3

To make or attempt to make something appear more important, likely, or obvious; to showcase or highlight.

4

To play (e.g. sport or music) more vigorously.

5

To be unfaithful to a lover; to cheat; used with on.

#slang