Deactivate Definition:

For a substituted aromatic ring, the effect of an electron withdrawing substituent that decreases the rate of electrophilic aromatic substitution.

Deactivate Explained:

Deactivation is the process in which the ring goes towards electrophilic automatic substitution. For example a highly positively charged Nitro group withdraws or moves away its electrons becoming electron negative, thus deactivating the ring. When removing the electron density from the ring, the Nitro group defragments its positive electric level and raises its energy level to prepare for its formation.