Leader of jaguars spotted cat heading off unknown risk (8)
I believe the answer is:
jeopardy
'risk' is the definition.
(I know that risk can be written as jeopardy)
'leader of jaguars spotted cat heading off unknown' is the wordplay.
'leader of' indicates taking the first letters.
'spotted cat' becomes 'leopard' (I've seen this in another clue).
'heading off' means to remove the first letter.
'unknown' becomes 'y' (algebra).
The initial letter of 'jaguars' is 'j'.
'leopard' with its initial letter taken off is 'eopard'.
'j'+'eopard'+'y'='JEOPARDY'
(Other definitions for jeopardy that I've seen before include "Hazard, risk" , "See 15" , "Danger of injury, loss, death, etc" , "Personal danger" , "Danger of harm" .)