__ hour (8)
I believe the answer is:
eleventh
'hour' is the definition.
(I have seen 'Last hour' mean 'eleventh' so perhaps 'hour' could also mean 'eleventh')
This is all the clue.
(Other definitions for eleventh that I've seen before include "This hour offers the last chance" , "Ordinal number" , "The hour to be saved at in the nick of time" , "Last to go in at Lord's" , "At this hour, it's the last possible moment" .)