【Abase】 , 【Debase】 , 【Demean】 , 【Degrade】 , 【Humble】 and 【Humiliate】 all mean to lessen in dignity or status.

【Abase】 suggests losing or voluntarily yielding up dignity or prestige.

• I watched my colleagues abasing themselves before the board of trustees.

【Debase】 emphasizes loss of worth or quality and especially deterioration of moral standards. (see also:  【Debase】 vs Vitiate vs Deprave vs Corrupt vs Debauch vs Pervert )

• Sport is being debased by commercial sponsorship.

【Demean】 suggests unsuitable behavior or association as the cause of loss of status. (see also: Behave vs Conduct vs Comport vs 【Demean】 vs Deport vs Acquit vs Quit )

• I wouldn't 【demean】 myself by asking for charity.

【Degrade】 suggests a downward step, sometimes in rank, more often in ethical stature, and typically implies a shameful or corrupt end. (see also:  【Degrade】 vs Demote vs Reduce vs Declass vs Disrate )

• When I asked him if he had ever been to a prostitute he said he wouldn't 【degrade】 himself like that.

【Humble】 frequently replaces 【degrade】 when the disgrace of a reduction in status is to be emphasized. (see also:  【Humble】 vs Meek vs Modest vs Lowly )

• He was humbled by the child's generosity.

【Humiliate】 implies the severe wounding of one's pride and the causing of deep shame.

• The party was humiliated in the recent elections.