armed to the teeth

‘ to be thoroughly equipped with weapons. ‘ — wiktionary.

to visualize this, just imagine a boarding party of pirates leaping onto the deck of the merchant ship they mean to plunder, each pirate with a dirk clenched firmly between his teeth, each armed with a cutl-ss and a brace or two of flintlock pistols. (the real-life pirate blackbeard further jazzed things up by twisting the ends of his bushy black beard into tendrils, which he then dipped into hot tallow. and just before he leaped from his ship onto the hapless merchantman, he would set his improvised candles on fire. the ignited candles transmogrified his face into the terrifying nightmare spectacle of the arch-demon escaped from h-ll).
example:

‘ she was already dressed for the party at the country club, already dominating a distinguished company she had yet to join.

‘ as she handed paul his c-cktail, he felt somehow inadequate, b-mbling, in the presence of her beautiful -ssurance . . .

‘ the expression “armed to the teeth” occurred to paul as he looked at her over his gl-ss. with an austere dark gown that left her tanned shoulders and throat bare, a single bit of jewelry on her finger, and very light make-up, anita had successfully combined the weapons of s-x, taste, and an aura of masculine competence.

‘ she quieted, and turned away under his stare. inadvertently, he’d gained the upper hand. he had somehow communicated the thought that had bobbed up in his thoughts unexpectedly: that her strength and poise were no more than a mirror image of his own importance, an image of the power and self-satisfaction the manager of the illium works could have, if he wanted it. in a fleeting second she became a helpless, bluffing little girl in his thoughts, and he was able to feel real tenderness toward her. ‘

— from kurt vonnegut’s 1952 novel “player piano” — chapter iv (page 35).