Certainly rare, yet tragic past (10)
I believe the answer is:
yesteryear
'past' is the definition.
('yesteryear' can be a synonym of 'past')
'certainly rare yet tragic' is the wordplay.
'certainly' becomes 'yes' (I've seen this before).
'tragic' indicates an anagram.
'rare'+'yet'='rareyet'
'rareyet' is an anagram of 'teryear'.
'yes'+'teryear'='YESTERYEAR'
(Other definitions for yesteryear that I've seen before include "Time disappeared" , "Former times" , "Rossetti's translation questioned whereabouts of its snows!" , "Days of old (poet.)" , "nostalgic time, perhaps" .)