Person involved in public relations regularly fell for bad lines (8)
I believe the answer is:
doggerel
'lines' is the definition.
(lines of poor quality poetry)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for doggerel that I've seen before include "Badly written poetry" , "Irregular comic verse" , "not great poetry" , "Poor quality comic or trivial verse" , "Badly written verse" .)