WordNet sense 1 (the financial means whereby one lives):

livelihood, living, support, sustenance

WordNet sense 2 (the main tower within the walls of a medieval castle or fortress):

dungeon, donjon

WordNet sense 3 (a cell in a jail or prison):

hold

WordNet sense 4 (fail to spoil or rot):

stay fresh

WordNet sense 5 (maintain in safety from injury, harm, or danger):

preserve

WordNet sense 6 (continue a certain state, condition, or activity):

continue, proceed, go on, go along

WordNet sense 7 (keep in a certain state, position, or activity; e.g.):

maintain

WordNet sense 8 (conform one's action or practice to):

observe

WordNet sense 9 (celebrate, as of holidays or rites):

celebrate

WordNet sense 10 (prevent from doing something or being in a certain state):

prevent

WordNet sense 11 (keep under control; keep in check):

restrain, suppress, hold back, keep back

WordNet sense 12 (allow to remain in a place or position):

retain, keep going, keep on

WordNet sense 13 (retain rights to):

save, keep open, hold open

WordNet sense 14 (retain possession of):

hold on

WordNet sense 15 (supply with necessities and support):

sustain