Regret shown in Peru especially (3)
I believe the answer is:
rue
'regret' is the definition.
(to rue something is to regret it)
'in peru especially' is the wordplay.
'in' indicates a hidden word.
'RUE' is hidden in the letters of 'peru especially'.
'shown' is the link.
(Other definitions for rue that I've seen before include "Plant producing oil" , "Bitter-tasting herb" , "Regret the bitter herb" , "Wish not to have been" , "Regret - wild shrub" .)