I had thing adjusted below a thousand — twelve (8)
I believe the answer is:
midnight
'twelve' is the definition.
(twelve o'clock)
'i had thing adjusted below a thousand' is the wordplay.
'i had' becomes 'i'd' (contraction).
'adjusted' indicates an anagram.
'below' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'a thousand' becomes 'M' (Roman numeral for a thousand).
'thing' anagrammed gives 'night'.
'id'+'night'='idnight'
'idnight' after 'm' is 'MIDNIGHT'.
(Other definitions for midnight that I've seen before include "Dim thing seen at witching hour" , "when it's usually dark" , "Twenty four hundred hours (or 0000) hrs" , "Twelve o'clock" , "-- Sun; -- blue" .)