Finish on board launches (5)
I believe the answer is:
sends
'launches' is the definition.
(I've seen this in another clue)
'finish on board' is the wordplay.
I cannot really see how this works, but
'finish' could be 'end' (synonyms) and 'end' is found within the answer.
'on board' could be 'ss' (I've seen this in other clues) and 'ss' is found within the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sends that I've seen before include "Despatches" , "Causes to go somewhere" , "Transmits" .)