Lacking money in country (5)
I believe the answer is:
minus
'lacking' is the definition.
(I've seen this before)
'money in country' is the wordplay.
'money' becomes 'm' (abbreviation used in economics).
'country' becomes 'US' (United States).
'm'+'in'+'us'='MINUS'
(Other definitions for minus that I've seen before include "Disadvantage" , "Take-away (sign)" , "deficiency" , "Lacking; below zero" , "Negative sign - negative thing" .)