I. noun
Synonyms: stimulus , catalyst, impetus, impulse, incentive, incitation, incitement, motivation, spur, stimulant
Related Word: compulsion, drive, impulsion; desire, lust, passion, urge, zeal
Antonyms: curb
II. verb
Synonyms: urge , egg (on), exhort, prick, prod, prompt, propel, sic, spur
Related Word: impel, move; coerce, compel, force; instigate