Fear inlet is engulfing city (5)
I believe the answer is:
alarm
'fear' is the definition.
(alarm is a kind of fear)
'inlet is engulfing city' is the wordplay.
'inlet' becomes 'arm' (I've seen this before).
'is engulfing' indicates putting letters inside.
'city' becomes 'la' (Los Angeles).
'arm' enclosing 'la' is 'ALARM'.
(Other definitions for alarm that I've seen before include "Noise giving warning" , "Daunt" , "Fright" , "Security device" , "State of (sudden) fear" .)