When someone is said to be "sticking at nothing", it means that they are completely determined and persistent in achieving their goals, no matter what obstacles come their way. There are several synonyms that can be used to describe this kind of resolute attitude, including "relentless", "unstoppable", "unfaltering", "indefatigable", and "tenacious". Each of these words evokes a sense of unwavering dedication and a refusal to be deterred by setbacks or challenges. Whether applied to a person, a goal, or a project, these synonyms all convey an impressive level of grit and determination that is essential for success.