Guard's van might show displeasure, just in case? (7)
I believe the answer is:
caboose
'guard's van' is the definition.
'caboose' can be an answer for 'van' (thesaurus). I am not sure about the 'guard's' bit.
'might show displeasure just in case?' is the wordplay.
I cannot quite see how this works, but
'show displeasure' could be 'boo' (synonyms) and 'boo' is located in the answer.
'case?' could be 'case' and 'case' is found in the remaining letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for caboose that I've seen before include "Kitchen on ship's deck" , "American at the rear" , "US train crew's accommodation" .)