Unmanageable figures with no opening within reach (10)
I believe the answer is:
cumbersome
'unmanageable' is the definition.
(similar in meaning)
'opening within reach' is the wordplay.
'opening' becomes 'umbers' (I am not sure about this - if you are sure you should believe this answer much more).
'within' means one lot of letters goes inside another.
'reach' becomes 'come' (I've seen this in other clues).
'umbers' going into 'come' is 'CUMBERSOME'.
'figures with no' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for cumbersome that I've seen before include "Unwieldy" , "Awkward" .)