Prepared to laugh at Henry still (8)
I believe the answer is:
although
'still' is the definition.
(thesaurus)
'prepared to laugh at henry' is the wordplay.
'prepared' indicates an anagram.
'at' means one lot of letters go next to another.
'henry' becomes 'H' (symbol for the unit of electrical inductance).
'to'+'laugh'='tolaugh'
'tolaugh' with letters rearranged gives 'althoug'.
'althoug'+'h'='ALTHOUGH'
(Other definitions for although that I've seen before include "In spite of the fact that" , "Notwithstanding" , "Despite the fact that (8)" , "However, but" , "Apart from the fact that" .)