Kissing someone's feet is an obsequious and submissive act of devotion. There are many synonyms for this gesture, including grovelling, fawning, toadying, bootlicking, and sycophancy. These words all describe actions where one humbles oneself to an individual in power. Another synonym for kissing someone's feet is crawling, which implies the idea of grovelling on all fours. However, it's best to avoid using the term "kissing someone's feet" as it perpetuates an outdated idea of subservience. Instead, words like respect, honor, and admiration, can be used to convey a similar sentiment without the connotation of submission and servitude.