Sped up series as contracted (6)
I believe the answer is:
narrow
'contracted' is the definition.
Both the definition and answer are adjectives. Maybe you can see a link between them that I can't see?
'sped up series' is the wordplay.
'sped' becomes 'ran' (running is a kind of speeding).
'up' is a reversal indicator (in down clue: letters go upwards).
'series' becomes 'row' (I've seen this before).
'ran' written backwards gives 'nar'.
'nar'+'row'='NARROW'
'as' is the link.
Can you help me to learn more?
(Other definitions for narrow that I've seen before include "Restricted - intolerant" , "Short of breadth" , "Keen" , "Strait, not broad" , "Strait, not wide" .)