If "hazy" refers to clarity of vision:
* Clear
* Sharp
* Distinct
* Defined
If "hazy" refers to clarity of memory or understanding:
* Clear
* Precise
* Specific
* Defined
If "hazy" refers to the atmosphere:
* Clear
* Sunny
* Bright
* Crisp
If "hazy" refers to a lack of detail or specifics:
* Detailed
* Specific
* Precise
* Definitive
Ultimately, the best antonym for "hazy" depends on the specific meaning you are trying to convey.