"So true!" (4)
(Other definitions for amen that I've seen before include "Word of approval" , "prayer's ending" , "Extremist" , "Approve" , "So let it be" .)
(Other definitions for preach that I've seen before include "Sermonise" , "Moralise" , "Give moral or religious advice" , "Give, eg, a sermon" , "Speak from the pulpit" .)