She's in a mess with German
I believe the answer is:
hessian
'german' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'she's in a mess' is the wordplay.
'she' becomes 'hess' (I can't justify this - if you can you should believe this answer much more).
'mess' is an anagram indicator.
'in'+'a'='ina'
'ina' with letters rearranged gives 'ian'.
'hess'+'ian'='HESSIAN'
'with' is the link.
Can you help me to learn more?
(Other definitions for hessian that I've seen before include "Jute clothing" , "Coarse jute fabric" , "sackcloth?" , "Coarse jute/hemp fabric" , "It's rather like sacking" .)