If "forbidding" means "unwelcoming" or "hostile":
* Inviting
* Welcoming
* Friendly
* Warm
* Hospitable
* Pleasant
If "forbidding" means "prohibiting" or "banning":
* Allowing
* Permitting
* Encouraging
* Authorizing
* Sanctioning
If "forbidding" means "threatening" or "menacing":
* Reassuring
* Comforting
* Safe
* Peaceful
* Harmless
If "forbidding" means "strict" or "severe":
* Lenient
* Permissive
* Tolerant
* Lax
* Easygoing
It is important to consider the specific meaning of "forbidding" in your context to choose the most appropriate antonym.