The Spanish verb 'guardar' (meaning 'to guard' or 'to keep') comes from Proto-Germanic 'wardōn' meaning 'to watch over, guard'. The Proto-Germanic word first evolved into the Spanish noun 'guarda' (meaning 'guard'), and then the verb suffix '-ar' was added to form 'guardar'. This evolution shows the characteristic Spanish development where Germanic 'w-' became 'gu-' at the beginning of words.

The Spanish noun 'guarda' (meaning 'guard' or 'guardian') is directly related to 'guardar', as it's the base noun from which the verb was formed. You might also encounter words like 'guardián' (guardian), 'guardia' (guard, watch), and 'guardería' (daycare, literally a 'guarding place'), all sharing the same root.

English speakers might recognize the connection to words like 'ward', 'warden', and 'guard', which all come from the same Proto-Germanic root 'wardōn'. The English 'guard' actually entered the language through French, which had borrowed it from Germanic sources similar to those that gave Spanish 'guardar'. This explains why 'guard' looks more similar to the Spanish word than 'ward' does, even though they're all related!