It's no good being just one in front (4)
I believe the answer is:
vain
'it's no good' is the definition.
(I've seen this before)
'just one in front' is the wordplay.
'just one' becomes 'i' (Roman numeral. I am not sure about the 'just' bit.).
'in' is an insertion indicator.
'front' becomes 'van' (I've seen this in another clue).
'i' put within 'van' is 'VAIN'.
'being' is the link.
Can you help me to learn more?
(Other definitions for vain that I've seen before include "Having too much pride in one's appearance" , "Conceited, puffed-up" , "Egotistical" , "Having an exaggerated sense of self-importance" , "Useless; conceited" .)