Green’s Dictionary of Slang

1. (orig. US) enthusiasm, vitality, energy, esp. as sex appeal.

1938		Pic (N.Y.) Mar. 8: come on, boys, send me gate. — play with umph. Prima wants an extra something from his swingsters.
1942		W. Winchell On Broadway 4 Oct. [synd. col.] Carole Landis drops in to give the battle some oomph.
1947		Dundee Courier 13 June 2/4: [headline] Scotland’s Lost Oomph.
1949		Wodehouse Mating Season 11: Corky has been wowing the customers with her oomph and espièglerie.
1960		Wodehouse Jeeves in the Offing 21: I had several times when under the influence of her oomph taken up with Roberta Wickham.
1978		S. King Stand (1990) 96: He’d never seen the kid with so little oomph in him.
1984		P. Corris ‘Heroin Annie’ in Heroin Annie [e-book] Sam tried to regain some of her oomph, but it was a losing battle, she was stoned and scared.
1999		Guardian Media 14 June 8: Posters, television, press, radio – have [...] lost their oomph.
2005		E. White My Lives 87: I need a real man [...] Someone who’s got some oomph.
2022		J. Hannaham Didn’t Nobody Give a Shit 19: Maybe she thought some extra visual oomph would get Carlotta buried under the jail.

2. a sexy, vivacious young woman.

c.1943

‘Bill O. Lading’ You Chirped a Chinful!! n.p.: Oomph: A girl who has loads of charm.