'Marrano' originates from Spanish, specifically the word 'marrano', where the term literally meant 'pig' or 'swine' and was used as a pejorative label.

'Marrano' passed from Spanish usage (16th century and later) as a derogatory label for certain New Christians; the term was recorded in English sources describing Iberian history and the Inquisition and came to denote converted Jews suspected of secret Jewish practice.

Initially it was a literal and coarse insult meaning 'pig' and was applied as a general pejorative; over time in English historical usage it came to refer specifically to Iberian converts suspected of secretly practising Judaism (crypto-Jews).