Dangerous to be high-spirited? F*** off! (5)
I believe the answer is:
risky
'dangerous' is the definition.
('risky' can be similar in meaning to 'dangerous')
'high-spirited? f off' is the wordplay.
'high-spirited?' becomes 'frisky' (I've seen this before).
'off' indicates named letters should be taken away.
'frisky' with 'f' removed is 'RISKY'.
'to be' acts as a link.
(Other definitions for risky that I've seen before include "Perilous" , "Unsafe" , "not playing safe" , "Hazardous" , "Having possibility of danger or loss" .)