Leader of scouts was concerned and frightened (6)
I believe the answer is:
scared
'frightened' is the definition.
(scared means frightened or fearful)
'leader of scouts was concerned' is the wordplay.
'leader of' says to take the initial letters.
'was concerned' becomes 'cared' (had a care).
The initial letter of 'scouts' is 's'.
's'+'cared'='SCARED'
'and' is the link.
(Other definitions for scared that I've seen before include "Thing which precipitates an event" , "Frightened or intimidated" , "having kittens" , "in fright" , "Fearful, anxious" .)