what is a waning moon?

thsi might sound dumb. what is a waning moon? is it when the moon is at half? how can i find out when the next waning moon is?

A waning moon is the period of time between full moon changing to new moon ^_^

It's also the phase the moon is in after it's full...so it's...well...you know...vaining lol
When the moon is full it shows ourself as a complete circle right?
Well, after the moon was full, it starts to fade away and the circle is not complete anymore...it's not filling up (waxing), it's
going to be a dark moon so the light of the sun wont reach it anymore...that's when we call it that it's vaining.

Thank you

what spells will work during this phase?