Less than totally? (3)

I believe the answer is:
all
This could be a double definition.
'less' is the first definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?
'totally?' is the second definition.
(I've seen this in another clue)
'than' acts as a link.
Can you help me to learn more?
(Other definitions for all that I've seen before include "and 18: 'Sing through -- --' (carol)" , "Avenue, walk or garden path" , "See 10 Across" , "nothing more" , "Fully clad ..." .)
