The Spanish verb 'chantajear' (to blackmail) has an interesting etymology that traces back to French. It comes from the Spanish noun 'chantaje' (blackmail), which was borrowed from the French word 'chantage' meaning the same thing. The French 'chantage' itself derives from the French verb 'chanter' (to sing). The Spanish verb was formed by adding the common verb-forming suffix '-ear' to 'chantaje'.

The semantic evolution from 'singing' to 'blackmail' in French (which was then borrowed into Spanish) likely originated from the idea of criminals threatening to 'sing' or reveal compromising information about their victims unless paid for their silence.

A simpler related Spanish word is 'cantar' (to sing), which comes from the same ultimate Latin root as French 'chanter', though it developed independently in Spanish. While 'cantar' maintained the original meaning of singing, its French cousin evolved to give us the more sinister meaning in 'chantajear'.

English speakers might recognize the connection to words like 'chant', 'chanty' (as in sea shanty), and 'enchant', which all come from the same French root 'chanter' meaning 'to sing'. While these English words maintained meanings related to singing or musical vocalization, the French development into 'blackmail' took a completely different semantic path.