in·duc·ible I. \ə̇nˈd(y)üsəbəl\adjective : capable of being induced II. adjective 1.: formed by a cell in response to the presence of its substrate < inducible enzymes > — compare constitutive 1a herein 2.: activated or undergoing expression only in the presence of a particular molecule < an inducible promoter that turns on its genes only in the presence of lactose >