The most succinct characterization of P'Gell is that she's a black widow who's never actually seen to bring about the deaths of her many husbands (unless they're really evil). Creator Will Eisner seems to have conceived her as something of a tongue-in-cheek version of the standard "femme fatale" of 1940s crime fiction, and as such many of P'Gell's encounters with the heroic Spirit have the tone of burlesque.
Nevertheless, though P'Gell bears a slight resemblance to DC's Catwoman, in that she usually wasn't out to cause serious harm to most of her victims, she was capable of violence, usually through pawns of some sort. For instance, she had an assassin kill off one husband, who was a nasty Nazi. Then she married the assassin-- but for some reason, he didn't last too long either.
It's ironic that the above cover-- designed for a 1973 Kitchen Sink reprint of several 1940s SPIRIT stories, and aimed at giving the collection a salacious vibe for the underground-comics market-- shows P'Gell on good terms with a more minor villainess, Pantha Stalk, as the two of them fondle the semi-conscious hero. In the only story in which the two females meet, P'Gell shoots Pantha dead to save the Spirit's life. Like Catwoman, P'Gell constantly attempted to persuade her masculine foe to join her in a life of crime. She never succeeded, though to the best of my recollection I don't believe he ever succeeded in jailing her. At best all the Spirit achieved was a draw-- and in all likelihood, the character, like his readers, may have preferred it that way.