The Spanish word 'fanfarrón', meaning 'boastful person' or 'braggart', has an interesting origin in Arabic. It comes from the Andalusi Arabic word 'farfar', meaning 'talkative person', which itself derives from Classical Arabic 'farfar', meaning 'unstable, talkative'. The sound change from 'farfar' to 'fanfarrón' shows the common linguistic process of dissimilation (where one 'r' sound changed to 'n') and the addition of the Spanish augmentative suffix '-ón', which often adds an intensive or pejorative meaning to words.

A related Spanish word is 'fanfarria', meaning 'fanfare' or 'boasting', which shares the same Arabic root. There's also the verb 'fanfarronear', meaning 'to brag' or 'to boast', which is directly derived from 'fanfarrón'.

While not directly related etymologically, the English word 'fanfare' (borrowed from French) has a similar sound and related connotations of showing off or making a showy display. The English word 'fanfaron' (though rare) was borrowed from Spanish 'fanfarrón' and has the same meaning of 'a braggart'.