Forest player on the bench, upset, attracting Hearts? (4)
I believe the answer is:
bush
'forest' is the definition.
(as in the Australian outback)
'player on the bench upset attracting hearts?' is the wordplay.
'player on the bench' becomes 'sub' (substitute in football, for example).
'upset' is a reversal indicator.
'attracting' says to put letters next to each other.
'hearts?' becomes 'h' (abbreviation used in card games e.g. bridge).
'sub' in reverse letter order is 'bus'.
'bus'+'h'='BUSH'
(Other definitions for bush that I've seen before include "A shrub or a modern president" , "Two US presidents" , "Bull is often associated with this" , "Scrub" , "Rural African" .)