Pious always taken in by endless tears (8)
I believe the answer is:
reverent
'pious' is the definition.
(similar in meaning)
'always taken in by endless tears' is the wordplay.
'always' becomes 'ever' (synonyms).
'taken in by' means one lot of letters goes inside another (back).
'endless tears' becomes 'rent' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ever' going within 'rent' is 'REVERENT'.
Can you help me to learn more?
(Other definitions for reverent that I've seen before include "Respectful, deferential" , "humble" , "Showing deep respect" , "Showing respect and veneration" , "Deeply respectful" .)