Sick ma lost? Very nearly! (6)
I believe the answer is:
almost
'very nearly' is the definition.
(I've seen this in another clue)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for almost that I've seen before include "Well-nigh" , "As good as" , "Not totally" , "Nearly, not quite" , "practically" .)