The Spanish word 'criminalista' (meaning 'criminalist' or 'criminal investigator') comes from combining the Spanish word 'criminal' with the suffix '-ista', which denotes a person who practices or studies something. The word 'criminal' itself derives from Latin 'criminalis' meaning 'relating to crime', which in turn comes from the Latin word 'crimen' meaning 'accusation' or 'offense'.

This etymology shows how the word developed from describing the concept of crime itself (crimen) to describing things related to crime (criminalis), and finally to describing a person who studies or investigates crimes (criminalista).

Some simpler, related Spanish words include 'crimen' (crime) and 'criminal' (criminal). These words share the same Latin root 'crimen' and are more commonly encountered in everyday Spanish. While 'criminal' refers to someone who commits crimes, 'criminalista' specifically refers to someone who studies or investigates crimes professionally.

English speakers can easily relate this word to familiar English words like 'crime', 'criminal', and 'criminalist', all of which share the same Latin ancestry. The English suffix '-ist' serves the same function as Spanish '-ista', both indicating a person who practices or specializes in something. This parallel makes 'criminalista' particularly easy for English speakers to remember and understand.