【Subservient】 ,  【servile】 ,  【slavish】 ,  【menial】 ,  【obsequious】  can mean showing or characterized by extreme compliance or abject obedience.

【Subservient】  (see also AUXILIARY ) applies directly or indirectly to those who occupy a subordinate or dependent condition or who manifest the state of mind of one in such a position; the term stresses subordination and may connote cringing or truckling.

【Servile】 suggests a lowly status and a mean or cringing submissiveness.

【Slavish】 suggests the status or attitude of a slave and typically implies an abject or debased servility unbecoming to a free man. Both  【servile】  and  【slavish】 are used of unduly close dependence upon an original or model.

【Menial】 in its typical extended reference applies to occupations requiring no special skill or intellectual attainment or ranked low in economic or social status and stresses the humbleness and degradation of or like that of one bound to such an occupation.

【Obsequious】 may apply to persons who are actual inferiors or to the words, actions, or manners by which they reveal their sense of inferiority in the presence of their superiors.

The word may imply a 【servile】 , often a sycophantic, attitude or extreme attentiveness in service or to the niceties of service.