Uneasy emperor entertains Victor, American (7)
I believe the answer is:
nervous
'uneasy' is the definition.
(I know that uneasy can be written as nervous)
'emperor entertains victor american' is the wordplay.
'emperor' becomes 'nero' (Roman emperor).
'entertains' is an insertion indicator.
'victor' becomes 'V' (phonetic alphabet: alpha, bravo, charlie etc.).
'american' becomes 'US' (abbreviation for United States).
'nero' going around 'v' is 'nervo'.
'nervo'+'us'='NERVOUS'
(Other definitions for nervous that I've seen before include "stewing" , "in a stew" , "Highly-strung" , "'Apprehensive, uneasy (7)'" , "far from cool?" .)