Irresponsible and secretive about a software substitute for litmus? (4-5)
I believe the answer is:
slap-happy
'irresponsible' is the definition.
I don't understand how the rest of the clue works.
(Other definitions for slap-happy that I've seen before include "free with the greasepaint?" , "Boisterously" , "Silly - unmethodical - punch-drunk" , "Cheerfully irresponsible" .)