I use dictionary definitions, such as these from Webster's Online Dictionary.

1. Inclined or willing to submit to orders or wishes of others or showing such inclination; "submissive servants"; "a submissive reply"; "replacing troublemakers with more submissive people."
2. Abjectly submissive; characteristic of a slave or servant; "she has become submissive and subservient."
3. Willing to submit without resistance to authority; deferent.
4. Inclined or ready to submit; acknowledging one's inferiority; yielding; obedient; humble.
5. Showing a readiness to submit; expressing submission; as, a submissive demeanor.
6. Being obedient, docile, biddable, acquiescent or unresisting.
7. Being subservient, servile, slavish or obsequious.
8. Being meek, gentle, mild or soft.
9. Being compliant, tractable, amenable or unstrained.
10. Adjective base of the adverb submissively.