Sickeningly upset most of malt whisky (9)

I believe the answer is:

mawkishly

I'm a little stuck... Click here to teach me more about this clue!

'sickeningly' is the definition.
Both the definition and answer are adverbs. Maybe you can see an association between them that I can't see?

'upset most of malt whisky' is the wordplay.
'upset' is an anagram indicator.
'most of' means to remove the last letter.
'malt' with its last letter removed is 'mal'.
'mal'+'whisky'='malwhisky'
'malwhisky' with letters rearranged gives 'MAWKISHLY'.

Can you help me to learn more?

(Other definitions for mawkishly that I've seen before include "sloppily" , "in sentimental vein?" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.