I. preposition
Etymology: Middle English
: repeatedly through : in at one side and out the other side of
thy slander hath gone through and through her heart — Shakespeare
II. adverb
Etymology: Middle English
1. : in every possible way or aspect : to the fullest extent : thoroughly
was through and through a liberal, a democrat, and a republican — Oscar Handlin
2. : all the way through : from one end to the other
a thunderstorm that drenched them through and through