To make a hole in, especially a cask of liquor, and put in a tap in order to draw the liquid.
To open, to make an opening into; to pierce.
French knights at Agincourt were unable to broach the English line.
To begin discussion about (something).
I broached the subject of contraceptives carefully when the teenager mentioned his promiscuity.
To be turned sideways to oncoming waves, especially large or breaking waves.
The small boat broached and nearly sank, because of the large waves.
To cause to turn sideways to oncoming waves, especially large or breaking waves (usually followed by to; also figurative).
Each time we came around into the wind, the sea broached our bow.