Soldier to finish getting cross? It seems absurd (7)
I believe the answer is:
paradox
'it seems absurd' is the definition.
(paradox can mean an absurd idea)
'soldier to finish getting cross?' is the wordplay.
'soldier' becomes 'para' (short for paratrouper).
'to finish' becomes 'do'.
'getting cross?' becomes 'x' (I am not sure about this - if you are sure you should believe this answer much more).
'para'+'do'+'x'='PARADOX'
Can you help me to learn more?
(Other definitions for paradox that I've seen before include "Seemingly sound, though self-contradictory, statement" , "Seemingly inconsistent statement" , "eg More haste, less speed" , "A seemingly contradictory statement" , "Ambiguity" .)