Femme fatale forgetting ultimate sacred word (6)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

MANTRAp; Collins has this as American English, usually hyphenated. Interestingly, the book Mantrap, by Sinclair Lewis, and the silent film based on it, directed by Victor Fleming, who later co-helmed Gone with the Wind, are both styled as a single word.