Reporting 100 who are too old (8)
I believe the answer is:
coverage
'reporting' is the definition.
(synonyms)
'100 who are too old' is the wordplay.
'c00 who are' becomes 'c' (I can't explain this - if you can you should believe this answer much more).
'too old' becomes 'overage' (I've seen this before).
'c'+'overage'='COVERAGE'
Can you help me to learn more?
(Other definitions for coverage that I've seen before include "Media reporting" , "policy provision" , "news attention" , "Treatment (of an issue) by the media" , "insurance" .)