Understanding there's nothing odd about Lennie drinking wine (7)
I believe the answer is:
'understanding' is the definition.
(an entente is an alliance or understanding)
'nothing odd about lennie drinking wine' is the wordplay.
'nothing odd about' indicates alternate letters (letters in odd-numbered positions are removed).
'drinking' is an insertion indicator (inserted letters are consumed or drunk).
'wine' becomes 'tent' (type of Spanish wine).
The alternating letters of 'lennie' are 'ene'.
'ene' going around 'tent' is 'ENTENTE'.
'there's' is the link.
(Other definitions for entente that I've seen before include "Informal alliance" , "A friendly understanding between countries, may be cordial" , "Agreement between governments" , "Interstate understanding" , "A friendly underatanding between countries, may be cordiale" .)