A companion or associate who copes or deals with something alongside another person; a fellow coper (archaic).
From 'copes' + 'mate' (companion, from Middle Dutch 'gemate'). This appears to be a rare or archaic compound combining 'cope' terminology with the common '-mate' suffix.
The word 'mate' comes from sailors' vocabulary—shipmates were literally the people you ate with (from 'mess mate')—and 'copesmate' suggests people who struggle together, which reflects how shared hardship bonds people more deeply than comfort.
Complete word intelligence in one call. Free tier — 50 lookups/day.