WordWeb Online

1. (arithmetic) make a subtraction
   "deduct this amount from my paycheque";
   - subtract, take off
    
2. Retain and refrain from disbursing; of payments
   "My employer is deducting taxes";
   - withhold, recoup
    
3. (logic) reason by deduction; establish by deduction
   - deduce, infer, derive

Derived forms: deducting, deducted, deducts

Type of: calculate, cipher, compute, conclude, cypher, figure [N. Amer], hold on, keep, reason, reason out, reckon, work out