Wrong impression of a key worker (7,5)

'wrong impression of a key worker' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'wrong impression of a key worker' is the wordplay.
I cannot quite see how this works, but
'wrong' could be 'error' (I've seen this before) and 'error' is found in the answer.
'worker' could be 'typist' (typist is a kind of worker) and 'typist' is found within the answer.
A single letter 's' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?