General synonyms:
* Forbearing
* Patient
* Understanding
* Open-minded
* Broad-minded
* Liberal
* Indulgent
* Accommodating
* Flexible
* Permissive
Synonyms related to specific contexts:
* Immune (to): Used when referring to resistance to something harmful.
* Resistant (to): Similar to "immune," but with a broader meaning.
* Enduring: Used to describe the ability to withstand hardship.
* Accepting: Used to describe the willingness to acknowledge something without judgment.
The best synonym to use will depend on the specific situation and the nuances you want to convey.