Tasteful quote by hermit extremely deep on reflection (9)
I believe the answer is:
aesthetic
'tasteful' is the definition.
(similar in meaning)
'quote by hermit extremely deep on reflection' is the wordplay.
'quote' becomes 'cite' (synonyms).
'by' means one lot of letters go next to another.
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'deep' becomes 'sea' (the deep can mean the sea).
'on reflection' says the letters should be written backwards.
'hermit' with its centre removed is 'ht'.
'cite'+'ht'+'sea'='citehtsea'
'citehtsea' in reverse letter order is 'AESTHETIC'.
(Other definitions for aesthetic that I've seen before include "Of pleasing appearance" , "Concerned with the appreciation of beauty" .)