Definition of sake noun from the Oxford Advanced Learner's Dictionary

sake

1noun
seɪk
 
; seɪk
 
 
see also sake2
Idioms

for Christ's, God's, goodness', heaven's, pity's, etc. sake

used to emphasize that it is important to do something or when you are annoyed about something
Do be careful, for goodness' sake.Oh, for heaven's sake!For pity's sake, help me!
Help
 
Some people find the use of Christ, God or heaven here offensive.

for something's sake

because of the interest or value something has, not because of the advantages it may bring
I believe in education for its own sake.art for art's sake

for the sake of somebody/something

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for somebody's/something's sake

in order to help somebody/something or because you like somebody/something
They stayed together for the sake of the children.You can do it. Please, for my sake.I hope you're right, for all our sakes (= because this is important for all of us).

for the sake of something/of doing something

in order to get or keep something
The translation sacrifices naturalness for the sake of accuracy.She gave up smoking for the sake of her health.Don't get married just for the sake of it.Let's suppose, for the sake of argument(= in order to have a discussion), that interest rates went up by 2%.
more at for old times' sake at old