Daft souvenir one dropped, being flustered (7)
I believe the answer is:
nervous
'flustered' is the definition.
(thesaurus)
'daft souvenir one dropped' is the wordplay.
'daft' is an anagram indicator.
'one' becomes 'i' (Roman numeral).
'dropped' suggests deleting specific letters.
'souvenir' with 'i' taken away is 'souvenr'.
'souvenr' is an anagram of 'NERVOUS'.
'being' acts as a link.
(Other definitions for nervous that I've seen before include "Easily agitated, timid" , "far from cool?" , "Fearful or apprehensive" , "Agitated and apprehensive" , "On edge, anxious" .)