Five of us oddly dear to French guarantor (7)
I believe the answer is:
voucher
'french guarantor' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'five of us oddly dear' is the wordplay.
'five' becomes 'V' (Roman numeral).
'of us' becomes 'ouch' (I can't explain this - if you can you should believe this answer much more).
'oddly' means one should take alternating letters (letters in the odd-numbered positions are used).
The alternating letters of 'dear' are 'er'.
'v'+'ouch'+'er'='VOUCHER'
'to' is the link.
Can you help me to learn more?
(Other definitions for voucher that I've seen before include "Document that serves as evidence of some expenditure" , "Ticket" , "Something that can be exchanged for goods or services" , "Document that can be exchanged for goods" , "Coupon; receipt" .)