As always, one can see nothing right in disease (7)
I believe the answer is:
forever
'as always one can see' is the definition.
Both the definition and answer are adverbs. Perhaps there's a link between them I don't understand?
'nothing right in disease' is the wordplay.
'nothing' becomes 'O' (O resembles 0).
'right' becomes 'r' (common abbreviation).
'in' means one lot of letters goes inside another.
'disease' becomes 'fever' ().
'o'+'r'='or'
'or' placed inside 'fever' is 'FOREVER'.
Can you help me to learn more?
(Other definitions for forever that I've seen before include "as diamonds are" , "continually" , "Till hell freezes over" , "Eternally" , "permanently" .)