Shm-reduplication is a form of reduplication in which the original word or its first syllable (the base) is repeated with the copy (the reduplicant) beginning with shm- (sometimes schm-), pronounced [ʃm].
The construction is generally used to indicate irony, derision or scepticism with respect to comments about the discussed object:
He’s just a baby!
Baby-shmaby. He’s already 5 years old!
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Shm-reduplication - Wikipedia (via interweber)
Automatic Linguistics Reblog (I get excited when I see the phonetic alphabet).