Missile sent up for town past Tokyo (7)
I believe the answer is:
torpedo
'missile' is the definition.
(missile from a submarine)
'sent up for town past tokyo' is the wordplay.
'sent up' says the letters should be written in reverse.
'for' becomes 'pro' (as in being 'pro' something).
'town' becomes 't' (abbreviation for town).
'past tokyo' becomes 'edo' (synonyms. I am not sure about the 'past' bit.).
'pro'+'t'='prot'
'prot' back-to-front is 'torp'.
'torp'+'edo'='TORPEDO'
Can you help me to learn more?
(Other definitions for torpedo that I've seen before include "Anti-ship weapon" , "Explosive underwater weapon" , "Trooped off with underwater missile" , "ruin" , "[SOMETHING FISHY]" .)