Move ahead before second eleven gradually gain more impetus (3,2,5)
I believe the answer is:
get up steam
'gradually gain more impetus' is the definition.
I know nothing about this answer so I can't tell whether this works.
'move ahead before second eleven' is the wordplay.
'move ahead' becomes 'getup' (getting up is a kind of moving. I am not sure about the 'ahead' bit.).
'before' says to put letters next to each other.
'second' becomes 's' (common abbreviation).
'eleven' becomes 'team' (eleven or XI can mean a football team).
'getup'+'s'+'team'='GET UP STEAM'
Can you help me to learn more?
(Other definitions for get up steam that I've seen before include "become excited" , "Gain more impetus in moving forward" .)