He has feats such as defeating Surtur (who can destroy a planet), conquering the 9 realms, and sealing away Hela. While there isn't much doubt that Thanos could beat Odin if he had all 6 stones, Odin could probably defeat Thanos if he only had one or two of them.

Was Thanos afraid of Odin?

Thanos is actually not afraid of anyone, but he sure did avoid Odin. Thanos is an extremely intelligent being, and he knows how strong Odin is. He isn't afraid of him, but he knows that by avoiding him and collecting Infinity Stones he can get to his goal without unnecessary risks.

Can Odin fight Thanos?

When Thanos faced Odin in Warlock #25, Odin spanked him outclassing him in terms of raw power. Not only does he fight Thanos but he handily dispatches the Silver Surfer in that same fight. ... Thanos survives his battle with Odin.