Continue in force with the very tiny and final period of time (4,6)
I believe the answer is:
last minute
'continue in force with the very tiny' is the definition.
I can't tell whether this definition defines the answer.
'final period of time' is the wordplay.
'final' becomes 'last' (synonyms).
'period of time' becomes 'minute' (minute is a kind of period of time).
'last'+'minute'='LAST-MINUTE'
'and' is the link.
Can you help me to learn more?
(Other definitions for last minute that I've seen before include "done at 23:59?" , "hurried in the end" , "with no time to spare" , "Not properly prepared" , "Final part of record" .)