Reportedly appear to join (4)
I believe the answer is:
seam
'join' is the definition.
(I know this)
'reportedly appear' is the wordplay.
'reportedly' shows a homophone (sound like).
'appear' becomes 'seem' (synonyms).
'seem' sounds like 'SEAM'.
'to' acts as a link.
(Other definitions for seam that I've seen before include "Join - stratum of ore" , "Line of sewing - stratum of coal" , "Stratum of ore or coal" , "Join - thin layer" , "A layer of coal in ground" .)