It sticks close to one spotted? (5)
I believe the answer is:
epoxy
'it sticks' is the definition.
The definition suggests a singular noun which matches the answer.
'close to one spotted?' is the wordplay.
'close to' indicates one should take the final letters (the close/ending of).
'spotted?' becomes 'poxy' (I can't justify this - if you can you should believe this answer much more).
The last letter of 'one' is 'e'.
'e'+'poxy'='EPOXY'
Can you help me to learn more?
(Other definitions for epoxy that I've seen before include "Type of adhesive/paint" , "Synthetic adhesive, paint etc." , "Adhesive; plastic" , "Synthetic polymer used in adhesives, paints, etc" , "Type of adhesive" .)