William combines Germanic elements usually rendered as "will" and "helmet" or "protection," giving a compound meaning close to "resolute protector." Centuries of royal and everyday use have kept the name tied to steadfastness -- less about aggression than about holding a position firmly. It reads as dependable rather than domineering, someone who stays when others might not.
The vertue of a Planet is in that House, whose beginning or cusp a Planet precedes by no greater space than five degrees. - William Lilly (1602.-1681.)