I got nan excited about Romeo in the dark (8)
I believe the answer is:
ignorant
'in the dark' is the definition.
(I've seen this before)
'i got nan excited about romeo' is the wordplay.
'excited' is an anagram indicator.
'about' is an insertion indicator.
'romeo' becomes 'r' (phonetic alphabet: alpha, bravo, charlie etc.).
'got'+'nan'='gotnan'
'gotnan' anagrammed gives 'gnoant'.
'gnoant' placed around 'r' is 'gnorant'.
'i'+'gnorant'='IGNORANT'
(Other definitions for ignorant that I've seen before include "Lacking knowledge or awareness" , "Lacking knowledge or lacking manners" , "Unenlightened" , "No rating for being uninformed" , "Rude or knowing very little" .)