The Spanish word 'doblez' comes from combining the Spanish word 'doble' (meaning 'double') with the suffix '-ez' which forms nouns indicating a quality or state. The word 'doble' itself comes from Latin 'duplus' meaning 'double' or 'twice'. The combination created 'doblez' which literally refers to a fold (something doubled over) and metaphorically came to mean duplicity or deception (having a double nature).

A simpler and more common related Spanish word is 'doble' meaning 'double'. While 'doble' simply refers to something being twice in amount or having two parts, 'doblez' took on the more specific meaning of a physical fold as well as the figurative meaning of being two-faced or deceitful.

English speakers can relate 'doblez' to words like 'double' and 'duplicate', which also come from the Latin 'duplus'. While these English words maintained meanings closer to the original 'two' or 'twice' sense, the Spanish 'doblez' developed more specific meanings related to folding and duplicity.