Speak at length with person living overseas missing queen (9)
I believe the answer is:
expatiate
'speak' is the definition.
(thesaurus)
'at length with person living overseas missing queen' is the wordplay.
I cannot quite see how this works, but
'at' is found in the answer.
'person' could be 'pi' (PI is an example) and 'pi' is found within the remaining letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for expatiate that I've seen before include "Speak or write at length about subject" , "Elaborate" , "In detail, discuss" , "write in great detail" , "Speak in detail (on)" .)