The Spanish word 'impávido' meaning 'fearless' comes from the Latin word 'impavidus', which had the same meaning. The Latin 'impavidus' was formed by combining two elements: the prefix 'in-' meaning 'not' and 'pavidus' meaning 'fearful'. 'Pavidus' itself came from the Latin verb 'pavere' meaning 'to be frightened'. So literally, 'impávido' means 'not fearful' or 'unafraid'.

A related Spanish word is 'pávido' (without the 'im-' prefix), which means 'fearful' or 'timid'. This comes directly from Latin 'pavidus'. Another related word is 'pavor', meaning 'terror' or 'dread', which comes from the same Latin root 'pavere'.

In English, we can find related words like 'panic', which ultimately comes from a similar root expressing fear or fright. While less common, the English word 'pavid' meaning 'timid' or 'fearful' is a direct borrowing from the Latin 'pavidus'. The word 'impavid' also exists in English, though it's quite rare, meaning 'fearless' just like its Spanish cousin 'impávido'.