What is antonym for gnaw?

There isn't one perfect antonym for "gnaw" because it has multiple meanings and the opposite would depend on the context. Here are some possibilities:

For the sense of biting or chewing:

* Nourish: If something is gnawing at you, it's consuming you negatively. Nourishing suggests something positive that sustains you.

* Soothe: If something is gnawing at your stomach, soothing would be the opposite.

* Heal: If something is gnawing at a wound, healing would be the opposite.

For the sense of worrying or troubling:

* Reassure: If something is gnawing at your mind, reassuring would be the opposite.

* Comfort: If something is gnawing at your heart, comforting would be the opposite.

* Calm: If something is gnawing at your nerves, calming would be the opposite.

For the sense of gradual destruction:

* Build: If something is gnawing away at a structure, building would be the opposite.

* Strengthen: If something is gnawing at your resolve, strengthening would be the opposite.

* Preserve: If something is gnawing at your health, preserving it would be the opposite.

The best antonym for "gnaw" depends on the specific situation and what you're trying to convey.