In front with one conclusion (5)
I believe the answer is:
ahead
'in front' is the definition.
(synonyms)
'with one conclusion' is the wordplay.
'with' says to put letters next to each other.
'one' becomes 'a' (a thing is one thing).
'conclusion' becomes 'head' (I can't explain this - if you can you should believe this answer much more).
'a' next to 'head' is 'AHEAD'.
Can you help me to learn more?
(Other definitions for ahead that I've seen before include "in van" , "In front as in race" , "In the vanguard" , "Forwards" , "Forward - in front" .)