Treat obtained by one in uncluttered entrance to eatery (9)
I believe the answer is:
negotiate
'treat' is the definition.
(I've seen this before)
'obtained by one in uncluttered entrance to eatery' is the wordplay.
'obtained' becomes 'got' ('get' can be a synonym of 'obtain').
'by one' becomes 'i' (Roman numeral. I am not sure about the 'by' bit.).
'in' means one lot of letters goes inside another.
'uncluttered' becomes 'neat' (I've seen this before).
'entrance to' indicates taking the first letters.
The initial letter of 'eatery' is 'e'.
'got'+'i'='goti'
'goti' put into 'neat' is 'negotiat'.
'negotiat'+'e'='NEGOTIATE'
Can you help me to learn more?
(Other definitions for negotiate that I've seen before include "Pass round" , "Try to reach agreement through discussion" , "Find a way over (a difficult path)" , "Bring about by mutual agreement" , "as diplomat does" .)