De-duct means to subtract or take away, so the antonyms of this word would mean to add or increase. Some antonyms for de-duct are add, give, include, incorporate, and combine. For example, if you add a bonus to your salary, you are increasing your income rather than deducting from it. Conversely, if you deduct taxes from your salary, you are taking away a portion of your income. Other antonyms for de-duct might include enhance, enlarge, magnify, expand, and supplement. Overall, the antonyms for de-duct convey the opposite meaning of taking away or reducing, instead emphasizing the act of adding or increasing.