Definition of preaches:
(v) :
(transitive) To proclaim by public discourse; to utter in a sermon or a formal religious harangue.
(v) :
(intransitive) To give a sermon.
(v) :
(transitive) To advise or recommend earnestly.
(v) :
(transitive) To teach or instruct by preaching; to inform by preaching.
(v) :
(intransitive) To give advice in an offensive or obtrusive manner.
(n) :
(obsolete) A religious discourse.