Can smeargle really learn ANY move?

Question

Even specialty moves,magma storm,fusion flare/bolt can smeargle learn them

Answer 1

Smeargle can learn every move through sketch except Chatter and Struggle. It will use Struggle if it runs out of PP, so technically the only move it cant use is Chatter. It can't Sketch Sketch, and Sketch is the only way it leans new moves. Even Judgement. I hope this helps! :)
-Jellohamster

Answer 2

Yes, it can via Sketch. Even the exclusive moves.

The only moves that Sketch has no effect on are Struggle and Chatter, as of Gen 5. That means that it is impossible for Smeargle to know Chatter, although if it runs out of PP, Smeargle can use Struggle.

Answer 3

In theory, yes.
However, bare in mind that this only applies for the Pokemon Games, and not for the online battle simulators such as Pokemon Online and Pokemon Showdown!. In games, all you need to do is Sketch the move you want from a Pokemon that can learn it.

On Pokemon Showdown!, there are some moves Smeargle learns which make it too overpowered in the metagame, so they are banned in competitive play. Hope I helped.