Green’s Dictionary of Slang

(US) energy, exuberance.

1944		J. O’Hara ‘Name in the Book’ in Good Housekeeping Dec. 38/1: [A] singularly uninspired and weary press agent, who didn’t happen to think that Minerva Hoffman, her real name, had what was then known as ‘voom.
2023		(con. 1962) J. Ellroy Enchanters 49: Her acting chops and alleged va-va-voom hit me flat.