:up: An idiom that means roughly* the same is (maybe only in Br English, and quite informal) 'carry the can': 'I don't care whose fault it is, but I've lost money and someone has to carry the can'.
b *But this idiom implies that possibly the person who 'carries the can' isn't really guilty.
As Anglika says, it's a new person. Quite a few new nouns are created by adding '-ie' to an adjective (e.g. 'sickie' - =day off 'sick'), and when the root word ends in a vowel sound (new -> newbie, free -> freebie) a /b/ gets added (to avoid a tricky diphthong).
An afterthought about 'take the blame for'. In these days of terrorism, an idiom you may well meet is 'claim responsibility for...'. When, after an atrocity, an anonymous caller phones the police to say 'It was the People's Liberation Front that planted the bomb' they're not 'taking the blame' but 'claiming responsibility'.