A possible threat to a tea-party host (3,6)
I believe the answer is:
mad hatter
'host' is the definition.
(I have seen 'host of party' mean 'mad hatter' so perhaps 'host' could also mean 'mad hatter')
'a possible threat to a tea-party' is the wordplay.
I cannot quite understand how this works, but
'a' is within the answer.
an anagram of 'threat' is 'hatter' which is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for mad hatter that I've seen before include "attending a literary tea party" , "Bizarre party host" , "Eccentric" , "Crazy man" , "Tea drinker" .)