In Pokemon Pearl, How do I teach my Exeggutor the attack Moonlight or Synthesis WITHOUT making it breeding?

I just want to know if I can teach my Exeguttor Moonlight or Synthesis. I know I can breed it with a pokemon that knows it to get an offspring that knows it but this Exeguttor is very very good with great IVs and Evs and attacks already. I just need Moonlight or Synthesis to make it perfect