High spirits make one of the family lose his head (7)
I believe the answer is:
elation
'high spirits' is the definition.
(synonyms)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for elation that I've seen before include "Delight, thrill" , "Feeling of joy and pride" , "It's a great feeling!" , "State of pleasure about toe-nail" , "Feeling of joy for it alone" .)