King in particular on head of large foreign coin (6)
I believe the answer is:
nickel
'foreign coin' is the definition.
'nickel' can be an answer for 'coin' (nickel is a kind of coin). I am unsure of the 'foreign' bit.
'king in particular on head of large' is the wordplay.
'king' becomes 'K' (abbreviation for king in chess).
'in' means one lot of letters goes inside another.
'particular' becomes 'nice' (nice can mean particular or precise).
'on' means one lot of letters go next to another.
'head of' indicates taking the first letters.
The first letter of 'large' is 'l'.
'k' put within 'nice' is 'nicke'.
'nicke'+'l'='NICKEL'
Can you help me to learn more?
(Other definitions for nickel that I've seen before include "US 5 cents" , "Metal - US coin" , "A 5-cent coin in USA" , "Metal; five US cents" , "US five cent piece" .)