One searches flower containing cotton, oddly (10)
I believe the answer is:
prospector
'one' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'searches flower containing cotton oddly' is the wordplay.
'searches flower' becomes 'prosper' (I can't explain this - if you can you should believe this answer much more).
'containing' means one lot of letters goes inside another.
'oddly' indicates alternate letters (letters in odd-numbered positions).
The alternate letters of 'cotton' are 'cto'.
'prosper' enclosing 'cto' is 'PROSPECTOR'.
Can you help me to learn more?
(Other definitions for prospector that I've seen before include "Searcher after valuable ores" , "One searching for valuable minerals" , "Clementine's father, perhaps?" , "Gold-digger" , "Searcher for minerals" .)