This is the 4762nd most frequent French word.
prétendu
"Prétendu" means "alleged" or "so-called."
Here, "prétendu" is used to suggest the status of the fiancé, possibly hinting at doubts or questioning the legitimacy of the relationship.
Elle est venue avec son prétendu fiancé.
She came with her supposed fiancé.
Though not using the exact word "prétendu," this sentence demonstrates the acting root "prétendre" linked to "prétendu," indicating someone's assertion which might not be accurate.
Il prétend être un expert, mais ses connaissances sont limitées.
He claims to be an expert, but his knowledge is limited.
In this context, "prétendu" denotes something considered or represented as true but not substantiated, often carrying a slightly skeptical tone.