Frost Giants are a monstrous, ancient race of titans from the icy world of Jotunheim, that were ruled by King Laufey. They have an ancient blood feud with the Asgardians, who've stolen their supremacy on the Nine Realms.
Frost Giants are a very durable, long lived race, comparable to Asgardian's. They are physically stronger than most Asgardian's, if not resistant to injury. They wear little if any arnour in contrast to Asgardian's.
Frost Giants have the ability to form ice out of the moisture from the atmosphere or perhaps even from their own bodies and shape it into tools like blades, spiked throwing balls, or solid ice pillars that can knock an Asgardian down. The ice made by the Frost Giants is obviously far harder than normal ice as it can injure Asgardian's. This can be seen by Odin All-Father's missing eye, the scars around his eye socket and when Fandral was impaled by an icicle created by a Frost Giant.