AP curently not in use? meaning?

[AC Question]

on Samsung tablet

 

[B. Diddy]

Welcome to Android Central! Which tablet? Where are you seeing that message, and when does it occur?

AP usually means Access Point, which is related to wi-fi. But it usually refers to the wi-fi router or hotspot, rather than something on the phone (unless, perhaps, if you have the phone's wi-fi hotspot turned on).