A word commonly used by older people (70 and up) around christmas. The older people ussually have no family left and care nothing for the festive seasons anymore.
Used to express grumpy dislike of somethinggenerally regarded as enjoyable, or as a response to someone who dislikes things that are normally liked by all.
Bah Humbug is usually used in a sentence that talks about something or someone they don't like, it is used in novels such as A Christmas Carol by Charles Dickens