Wasteful academic delayed welcoming soldier back (10)
I believe the answer is:
profligate
'wasteful' is the definition.
(similar in meaning)
'academic delayed welcoming soldier back' is the wordplay.
'academic' becomes 'prof' (short for professor).
'delayed welcoming soldier back' becomes 'ligate' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'prof'+'ligate'='PROFLIGATE'
(Other definitions for profligate that I've seen before include "Wastrel" , "Wildly extravagant" , "Recklessly extravagant" , "extravagant type" , "Dissolute" .)