Hundred flee safe place beside oddly used road (6)
I believe the answer is:
avenue
'road' is the definition.
(avenue is a kind of road)
'hundred flee safe place beside oddly' is the wordplay.
I cannot really see how this works, but
'hundred' could be 'a' (synonyms) and 'a' is located in the answer.
'place' could be 'venue' (I've seen this before) and 'venue' is located in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'used' is the link.
Can you help me to learn more?
(Other definitions for avenue that I've seen before include "suburban street" , "Wide, straight road" , "Broad road or street, often with trees" , "A wide street or access route" , "Wide street or path to progress" .)