Article on a smart UK foreign relations manual (4,5)
I believe the answer is:
kama sutra
'relations manual' is the definition.
(ancient book about sexual relations)
'article on a smart uk foreign' is the wordplay.
'article' becomes 'a' (example of the part-of-speech).
'on' means one lot of letters goes inside another.
'foreign' indicates anagramming the letters (foreign order of the letters).
'a'+'smart'+'uk'='asmartuk'
'asmartuk' is an anagram of 'kmasutra'.
'a' put inside 'kmasutra' is 'KAMA SUTRA'.
(Other definitions for kama sutra that I've seen before include "Hindu exotic text" , "the other illustrations" , "Ancient Sanskrit text on sexual love" , "Hindu sex manual" , "Sanskrit treatise on the art of love" .)