The condition, state, or quality of being at an end; in obsolete or rare usage, the culmination or termination of something.
From 'end' combined with '-ship' (Old English suffix '-scipe' meaning state or condition, as in 'friendship'), a formation that was more productive in Middle English but is now largely archaic.
Like 'friendship' and 'leadership,' 'endship' shows how '-ship' once freely created nouns for states of being, but this particular word faded because we prefer simpler words like 'ending' or 'termination'.
Complete word intelligence in one call. Free tier — 50 lookups/day.