Today's word is..
Ultracrepidate [ul-tra-crep-i-date; pron, ul-tre-krep'i-date]
To criticise beyond sphere of one’s knowledge.
Latin, from ultra (beyond), and crepida (sandal). Makes sense. No, really! Read on..
In a Roman story, a cobbler criticised the sandals in a painting by the painter, Apelles, saying there was one loop too few. Apelles fixed the mistake, and bolstered by this the cobbler complained about further parts of the work - to which Apelles is said to have replied, "Ne sutor ultra crepidam," or, roughly, "The cobbler must not go beyond the sandal" and advise him to not critisise beyond his own sphere of knowledge.
Though undoubtedly placed in his position for some good reason or other, it was a frequent source of frustration for nerdfury when his temporary supervisor for the week would, during coaching sessions, pull up copies of his emails to clients and ultracrepidate on his skills at writing - marking him down on assessments over his own lack of understanding for the correct use of the King's English.
Finally, a great reason to use my grammar icon! :D