The Spanish word 'fácil' (meaning 'easy') comes from the Latin word 'facilis', which also meant 'easy' or 'feasible'. The Latin 'facilis' was formed by combining two parts: the verb 'facere' meaning 'to do, to make' and the suffix '-ilis' which was used to form adjectives indicating capability. So literally, 'facilis' described something that was 'able to be done' or 'doable', which evolved to mean 'easy'.

Several common Spanish words share the same Latin root 'facere': 'hacer' (to do/make), 'difícil' (difficult), 'facilitar' (to facilitate), and 'facultad' (faculty, ability). All these words relate to the basic concept of 'doing' or 'making' something.

Many English words are related to 'fácil' through the Latin root 'facere': 'facile' (easy but in a negative sense), 'facilitate' (to make easier), 'facility' (ease of doing something), 'fact' (something done or made), and even 'difficult' (not easy to do). The '-ible/-able' endings in English words like 'feasible', 'possible', and 'terrible' come from the same Latin suffix '-ilis' that helped form 'fácil'.