nail your colours to the mast

To "nail your colours to the mast" means to fully and publicly declare and support one's beliefs, opinions, or loyalties even in the face of opposition or adversity. The phrase originates from naval warfare, where ships would hoist their flags, or "colours," on the mast to identify their allegiance. Nailing the colours to the mast demonstrated a commitment and unwillingness to retreat, symbolizing a willingness to stand firm in one's convictions. Thus, when someone is said to "nail their colours to the mast," they are figuratively showing their unwavering support and determination.