Strength of character. Wilfulness. Courage. Having the determination to succeed. Pride.
When this card appears it is usually an indication of having to stand your ground over a principle or ethic. There is a lot of energy and willpower here but also a caution to check that you are standing firm for the right reasons and not just being childishly obstinate because you're not getting your own way. There is the possibility of courageous action here if the will is used for the greater good. There is a certain amount of arrogance inherent in this card, and care needs to be taken to ensure that it's not out of proportion to the matter at hand.
Mars in Leo which is willfulness and dramatic action.
Examples With Other Cards
Justice will emphasise the need to stand firm over your principals and ethics. The cards following will show how things will proceed if you continue to hold firm. Any court cards can be indicators of the people who may be getting in your way. The major arcana cards will show useful people that are there to help, or they could be other aspects of yourself that will be brought to the fore.