Maybe the last men to show regrets (7)
I believe the answer is:
laments
'regrets' is the definition.
('lament' can be a synonym of 'regret')
'maybe the last men' is the wordplay.
'maybe' indicates anagramming the letters.
'last'+'men'='lastmen'
'lastmen' with letters rearranged gives 'LAMENTS'.
'to show' acts as a link.
(Other definitions for laments that I've seen before include "Bemoans" , "complaints" , "Mourns" , "Sad songs" , "elegies" .)