'hermitically' originates from English, specifically the adverbial formation from the adjective 'hermitical' (formed by adding the suffix '-ly'); 'hermitical' comes from Late Latin 'eremicus'/'eremita' (from Greek 'erēmítēs'), where the Greek root referred to a 'person of the desert' or 'hermit'.

'hermitical' changed from Medieval Latin 'eremita'/'eremicus' (and Old French forms such as 'ermite') and eventually became the English adjective 'hermitical'; the adverb 'hermitically' was formed later by adding the English adverbial suffix '-ly'.

Initially, it meant 'of or pertaining to a hermit (living in seclusion)'; over time the word has kept the sense of 'reclusive' but has sometimes been confused with 'hermetically' (which originally meant 'of Hermes/Hermeticism' and later came to mean 'airtight').