Lose pals in mountain range (4)
I believe the answer is:
alps
'mountain range' is the definition.
(Alps is an example)
'lose pals' is the wordplay.
'lose' is an anagram indicator (I've seen 'lost' mean this).
'pals' with letters rearranged gives 'ALPS'.
'in' is the link.
(Other definitions for alps that I've seen before include "European mountains" , "Mont Blanc is therein" , "Mountain system in south-central Europe" , "Pals seen in mountains" , "With pals in great mountains" .)