a. 1. Capable of being deducted, taken away, or withdrawn. [ 1913 Webster ]
Not one found honestly deductible From any use that pleased him. Mrs. Browning. [ 1913 Webster ]
2. Deducible; consequential. [ 1913 Webster ]
adj. not allowable as a tax deduction; as, political contributions are nondeductible. Opposite of deductible. [ WordNet 1.5 ]