Critical half-hour for the little man (6)
I believe the answer is:
urgent
'critical' is the definition.
(I've seen this before)
'half-hour for the little man' is the wordplay.
'half' means to take half the letters.
'for' is a charade indicator (letters next to each other).
'the little man' becomes 'gent' (gent is a kind of man. I am not sure about the 'little' bit.).
'hour' cut in half is 'ur'.
'ur'+'gent'='URGENT'
Can you help me to learn more?
(Other definitions for urgent that I've seen before include "Calling for immediate attention" , "Of immediate importance" , "Requiring early action" , "Earnest, insistent" , "Pressing, immediate" .)