Plug project by soldier, senior officer's aide (8)
I believe the answer is:
adjutant
'senior officer's aide' is the definition.
'adjutant' can be an answer for 'aide' (synonyms). I am not certain of the 'senior officer's' bit.
'plug project by soldier' is the wordplay.
'plug' becomes 'ad' (as in plugging a product).
'project' becomes 'jut' (I've seen this in another clue).
'by' means one lot of letters go next to another.
'soldier' becomes 'ant' (soldier is a type of ant).
'ad'+'jut'+'ant'='ADJUTANT'
Can you help me to learn more?
(Other definitions for adjutant that I've seen before include "Aide-de-camp" , "CO's aide" , "Officer who helps" , "Officer's assistant" , "one with large bill" .)