One would eschew leaders in Roman days (4)
I believe the answer is:
ides
'roman days' is the definition.
(I've seen this in another clue)
'one would eschew leaders in' is the wordplay.
'one' becomes 'is' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'would' becomes 'd' (as in 'we'd' - 'we would').
'leaders' suggests taking the first letters.
'in' is an insertion indicator.
The initial letter of 'eschew' is 'e'.
'd'+'e'='de'
'is' enclosing 'de' is 'IDES'.
Can you help me to learn more?
(Other definitions for ides that I've seen before include "Period in month" , "Orfes" , "Side of March when Caesar died" , "March day fatal to Julius Caesar" , "Caesar's fateful day" .)