Teutonic sentry's pet (6,8)
I believe the answer is:
german shepherd
'pet' is the definition.
The definition and answer can be both animals as well as being singular nouns.
Maybe there's an association between them I don't understand?
'teutonic sentry's' is the wordplay.
'teutonic' becomes 'German' (synonyms).
'sentry's' becomes 'shepherd' (I can't explain this - if you can you should give a lot more credence to this answer).
'german'+'shepherd'='GERMAN SHEPHERD'
Can you help me to learn more?
(Other definitions for german shepherd that I've seen before include "Alsatian" , "one wearing dog collar?" .)