Learning Spells from other Classes

When you level up, you may attempt to learn a spell from a spell list different from your class. As stated in Pg.287 of the DMG, this can significantly reflavor your character. Obtaining a spell from a different spell list in this way is NOT meant to be a buff, but instead is meant to allow your character to align themselves more closely with their flavour. A simple example is allowing a Necromancer Wizard to learn the Necromancy spell Inflict Wounds, which is normally a Cleric spell.

Depending on the power level of the spell, the DM may ask you to provide a spell scroll, a certain amount of time of study, special material components, or another requirement altogether. Depending on your class and the spell, additional restrictions may be put in place.

Talk to the DM before learning any spell not in your spell list. A druid should not be able to learn Fireball, as it would be much too powerful in Wildshaped form. Similarly, a warlock with wizard spells would be entirely too powerful. If you wish to learn some of these powerful spell/feature combinations consider multiclassing, as it has a direct drawback incorporated already.