Well, neither, really.
Increscent describes something that's increasing in size. The word is most usually used to describe the moon.
How can you tell if the moon where you are is getting bigger or getting smaller? You look to see which side of the moon is shining. If the shiny bit of the moon is on the Right it's Returning (ie, moving towards a full moon); and if the shiny bit of the moon is on the Left it's Leaving (on its way to no visible moon at all).
Sadly the moon's just past the full at the moment, so you won't be seeing an increscent moon for a couple of weeks.
Still, if you see a lady in an expectant condition; or have a balloon that needs blowing up; or are in a climate where pumpkins are growing; or a place where frogs are singing;
Western Chorus frog
or you've bumped your head rather hard; or have ever seen a molehill appear; or have put a cake in an oven, then you will have spotted something increscent.
photo by Crystal
And when the moon does begin to wax again, you'll have an extra reason to feel pleased with yourself.
Spot the Frippet: something increscent. This word comes from the Latin incrēscēns, which is to do with swelling or growing.