General synonyms:
* Sufficient
* Adequate
* Ample
* Satisfactory
* Abundant
* Plenty
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More specific synonyms:
* For quantity: sufficient, ample, abundant, plenty
* For quality: adequate, satisfactory
* For time: long enough, sufficient time
* For money: affordable, reasonable, within budget
Informal synonyms:
* Good enough
* That'll do
* Plenty
* All right
* That's it
The best synonym for "enough" will depend on the specific situation and the tone you want to convey.