Odd time almost completely quiet (10)
I believe the answer is:
uneventful
'quiet' is the definition.
(similar in meaning)
'odd time almost completely' is the wordplay.
'odd' becomes 'uneven' (odd rather than even).
'time' becomes 't' (abbreviation).
'almost' means to remove the last letter (most of the word but not all of it).
'completely' becomes 'full' (full could historically mean fully).
'full' with its final letter removed is 'ful'.
'uneven'+'t'+'ful'='UNEVENTFUL'
(Other definitions for uneventful that I've seen before include "Quiet" , "dull" , "without much happening" , "without incident" .)