Henry getting answer twice? That’s a laugh (2-2)
I believe the answer is:
ha-ha
'that's a laugh' is the definition.
(I've seen this before)
'henry getting answer twice?' is the wordplay.
'henry' becomes 'H' (symbol for the unit of electrical inductance).
'getting' means one lot of letters go next to another.
'answer' becomes 'a' (abbreviation eg in Q and A).
'twice?' shows that letters should be duplicated (I've seen 'twice' mean this).
'h'+'a'='ha'
'ha' duplicated is 'HA-HA'.
(Other definitions for ha-ha that I've seen before include "Hidden ditch" , "Ditch with wall in it - sounds merry" , "Funny type of ditch?" , "that I find amusing" , "Ditch with wall in it - sounds hilarious" .)