Cross words in castle (7)
I believe the answer is:
windsor
'castle' is the definition.
(I've seen this before)
'cross words in' is the wordplay.
'cross' indicates an anagram (a cross or irritated version of the letters).
'words'+'in'='wordsin'
'wordsin' with letters rearranged gives 'WINDSOR'.
(Other definitions for windsor that I've seen before include "Royal castle; a tie knot" , "Thames town" , "former German house?" , "Royal palace" , "Home to Shakespeare's merry wives" .)