ravenous : voracious
The pair that would best complete the analogy "propitious: favorable" is "auspicious: promising." Both pairs share a similar meaning, with "propitious" and "auspicious" indicating something that is likely to lead to success or good outcomes, while "favorable" and "promising" both suggest positive conditions or prospects.
A team may choose to decline a penalty in football if the penalty would give them a disadvantage or if the result of the play is more favorable than the penalty yardage.
hot : cold
impressive : grand
slay : spare
independence : slavery
reveal : conceal
hot : cold
courage : bravery
stimulate : excite
awareness indifference
Honesty : lying