A few things to ask.

[AEZ]

Hi,I don't really know where I should ask about this.I hope I'm in the right place.

1)If I hatch a Pokemon legitimately on Platinum,let say,a Beldum and train it,but then I trade it to my Diamond,which is hacked to make all pokemon shiny,then I trade it to Platinum again.The Beldum will be shiny.Is it considered a hacked pokemon??Coz I still hatch n train it legitimately.Only it's shininess is hacked.

2)How about if I hacked TMs and teach it to my Pokemons??

 

[Mitchman]

It would be considered a hacked Pokemon as its shiny status would be obtained through cheating but the TM thing I dunno.

 

[AEZ]

will it still be able to enter the GTS??

 

[Blazevoir]

Next time, use the Simple Questions thread.

To answer your question, yes, it is considered hacked by the majority of the fandom if you hack it to be shiny or if you teach it moves from hacked TMs. The GTS probably would allow it since I don't think it does a check for hacked shinies.