'slowly-ended' originates from the combination of 'slowly' and 'end', where 'slowly' means 'at a slow pace' and 'end' means 'to bring to a conclusion'.

'slowly-ended' changed from the phrase 'slowly end' and eventually became the modern English adjective 'slowly-ended'.

Initially, it meant 'to end something slowly', but over time it evolved into its current meaning of 'describing something that has come to a gradual conclusion'.