Whine is a stat changing move that sharply drops your opponents Defense, thus making your attacks more effective. Considering the level this move is learned at, it's better to not bother learning it since most of your attacks will probably be able to finish off opponents with one hit (this was written during v0.2).
"An ear-splitting screech is emitted to sharply reduce the foe's DEFENSE."
Dmnd Tiara - Lvl 24
DISCLAIMER: More ponies may need to be added upon further expansion.