Most of expected lines will be boring (4)
I believe the answer is:
dull
'be boring' is the definition.
(similar in meaning)
'most of expected lines' is the wordplay.
'most of' means to remove the last letter.
'expected' becomes 'due' (similar in meaning).
'lines' becomes 'll' (l is an abbreviation for line).
'due' with its final letter taken away is 'du'.
'du'+'ll'='DULL'
'will' is the link.
(Other definitions for dull that I've seen before include "Cloudy or boring" , "Uninspiring" , "mat" , "Slow-witted - tedious - cloudy" , "Not shiny; uninteresting" .)