One who offers gratuitous suggestions? (11)
I believe the answer is:
freethinker
'one who' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'gratuitous suggestions?' is the wordplay.
'gratuitous' becomes 'free' (synonyms).
'suggestions?' becomes 'thinker' (I can't justify this - if you can you should believe this answer much more).
'free'+'thinker'='FREETHINKER'
'offers' is the link.
Can you help me to learn more?
(Other definitions for freethinker that I've seen before include "Someone with opinions formed independently" , "Person with their own religious beliefs etc" , "Person not holding generally accepted beliefs" , "Rationalist" , "Person who rejects accepted opinions" .)