General - This is the most common antonym, meaning broad or not detailed.
Vague - This implies a lack of clarity or precision.
Indefinite - This suggests something is not clearly defined or limited.
Abstract - This refers to something that is theoretical or not concrete.
Broad - This emphasizes a wide scope or range.
Uncertain - This indicates something is not sure or definite.
Ambiguous - This implies something can be interpreted in multiple ways.
Universal - This refers to something that applies to everything or everyone.
Generalizable - This suggests something can be applied to a wider range of situations.
The best antonym for "specific" will depend on the particular context and what you want to emphasize.