In phenol, the OH group has -I effect due to electronegative oxygen. So, OH group should deactivate the benzene ring towards electrophilic substitution.
[P.S.: I am not talking about the o,p-directing ability of OH, which appears due to lone pair. Also please do not suggest me the question at the link Why is a hydroxyl group more activating than a methoxy group in electrophilic aromatic substitution?, because that is not what I am looking for.]