Conservative Minister lacking some guts - he'll be moving sideways (4)
I believe the answer is:
crab
'lacking some guts he'll be moving sideways' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'conservative minister' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'minister' becomes 'rab' (I can't justify this - if you can you should give a lot more credence to this answer).
'c'+'rab'='CRAB'
Can you help me to learn more?
(Other definitions for crab that I've seen before include "move obliquely" , "winch" , "Seashore creature" , "A crustacean; type of apple" , "One may be caught" .)