Cautious cleaning lady ultimately busy (5)
I believe the answer is:
chary
'cautious' is the definition.
('chary' can be similar in meaning to 'cautious')
'cleaning lady ultimately busy' is the wordplay.
'cleaning lady' becomes 'char' ('char' can be a synonym of 'cleaning lady').
'ultimately' suggests the final letters.
The last letter of 'busy' is 'y'.
'char'+'y'='CHARY'
(Other definitions for chary that I've seen before include "Careful" , "Circumspect" , "Cautiously reluctant" , "cagy" , "Cautious, wary" .)