Unusually quiet, almost timid person (11)
I believe the answer is:
milquetoast
'timid person' is the definition.
'Milquetoast' can be an answer for 'person' (Milquetoast is an example). I am not certain of the 'timid' bit.
'unusually quiet almost' is the wordplay.
'unusually' is an anagram indicator.
'quiet'+'almost'='quietalmost'
'quietalmost' is an anagram of 'MILQUETOAST'.
Can you help me to learn more?
(Other definitions for milquetoast that I've seen before include "Person who is timid" , "Timid chap" .)