Certainly uncommonly teary about Queen in the past (10)
I believe the answer is:
yesteryear
'in the past' is the definition.
(I've seen this before)
'certainly uncommonly teary about queen' is the wordplay.
'certainly' becomes 'yes' (I've seen this before**).
'uncommonly' indicates anagramming the letters.
'about' indicates putting letters inside.
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'teary' with letters rearranged gives 'tyear'.
'tyear' placed around 'er' is 'teryear'.
'yes'+'teryear'='YESTERYEAR'
(Other definitions for yesteryear that I've seen before include "Period 14 [CENTENARIAN] lived through" , "Former times" , "nostalgic time, perhaps" , "Nostalgic days" , "Twelve months ago" .)