General synonyms:
* Artistic
* Beautiful
* Elegant
* Pleasing
* Stylish
* Visually appealing
* Harmonious
* Graceful
* Charming
More specific synonyms:
* Artful (emphasizes skill and craftsmanship)
* Sophisticated (emphasizes refinement and complexity)
* Tasteful (emphasizes good judgment and appropriateness)
* Expressive (emphasizes the ability to communicate emotions)
* Evocative (emphasizes the ability to inspire feelings and ideas)
* Formal (emphasizes adherence to established principles of beauty)
* Informal (emphasizes a casual and relaxed approach to beauty)
Synonyms related to specific fields:
* Formalist (in art criticism)
* Formalistic (in art criticism)
* Functional (in design)
* Ergonomic (in design)
* Minimalist (in design)
* Avant-garde (in art)
* Classical (in art and architecture)
* Modernist (in art and architecture)
Ultimately, the best synonym for "aesthetic" will depend on the specific context in which you are using it.