If "singe" means to burn slightly:
* Soak: To make something completely wet, the opposite of being slightly burned.
* Drench: Similar to soak, but with more emphasis on the amount of liquid used.
* Moisturize: To add moisture to something, the opposite of drying out.
* Hydrate: Similar to moisturize but more scientific, often used for living things.
If "singe" means to damage slightly:
* Repair: To fix something that's been damaged.
* Restore: To bring something back to its original condition.
* Preserve: To protect something from damage.
If "singe" means to burn the hair off something:
* Groom: To carefully brush and clean an animal's fur.
* Trim: To cut the ends of something, like hair.
* Fluff: To make something soft and fluffy, the opposite of singeing hair.
The best antonym will depend on the specific situation.