It´s like man, dude, guy(s),...

That's not spanish !, It's Spain's netspeak, and It's not even.. popular. It's basically a diminutive for "tronco" which means "dude" in some parts of Spain.

no lo sé, a lo mejor será un modismo osea una palabra que sólo usan en uno que otro país, tronkis me suena a árbol o no sé tal vez sea un apodo i don't know maybe would be a slang word because here in méxico doesn't have any meaning, tronki sounds like tree or perhaps is a nickname i wish i help you a kinda, and sorry by my crepy english, i'll be better :D

If you want to learn Spanish, try to find other partners that use a better language.

It is a vulgar word and it means "colega" "amigo" "tío,con significado de amigo no de pariente","tronco"