Change or Adjustment:
* Acclimatization
* Alteration
* Modification
* Transformation
* Evolution (in a biological context)
Transformation for a Specific Purpose:
* Conversion
* Reconfiguration
* Reworking
* Adjustment
* Modification
Making Something Suitable:
* Suitability
* Fitness
* Amelioration
* Improvement
In the Context of Art/Literature:
* Version
* Interpretation
* Remake
* Paraphrase
For a Specific Situation:
* Compromise
* Accommodation
* Concession
It's important to consider the specific context when choosing a synonym for "adaptation". For example, if you're talking about a biological process, "evolution" might be the best choice. However, if you're talking about a movie adaptation of a book, "version" or "remake" would be more appropriate.