One watches Waterloo KO Uttoxeter, missing part of it (7)
I believe the answer is:
Here is my best explanation:
'one' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'watches waterloo ko uttoxeter missing part of it' is the wordplay.
'missing part of it' indicates the answer is hidden within the clue.
'LOOKOUT' is hidden within 'watches waterloo ko uttoxeter'.
(Other definitions for lookout that I've seen before include "Vantage point", "Nightwatchman", "Beware - keep a sharp eye open", "View", "Sentinel, watcher", "Be on your guard!", "Sentry, guard", "Person keeping watch", "Watching person" and "Sentry, one who keeps watch".)