v. t. [ imp. & p. p. inactivated p. pr. & vb. n. inactivating. ] to make inactive; as, boiling will inactivate most enzymes; acetylation of the antibiotic inactivated it.
Syn. -- deactivate. [ WordNet 1.5 +PJC ]

☞ To inactivate an enzyme or chemical usually renders it permanently inactive; to inactivate a machine (as by turning a switch) may be reversible, and for machines and devices, the term deactivate is usually used. The distinction is worth preserving.
[ PJC ]