ADJECTIVE
1 informal attributive Relating to Birmingham or the dialect of English spoken there.
2 dated attributive Cheap, showy, or counterfeit.
‘a vile Brummagem substitute for the genuine article’
Origin
Mid 17th century: dialect form of Birmingham, England; Brummagem (sense 2 of the adjective) is with reference to counterfeit coins and cheap plated goods once made there.
Term used by some men to indicate that they believe an otherwise very attractive woman has been given extra "points" or "bumps" up a scale by other men, thus grading them higher in the Hottie Scale (of 1 to 10) then they should be.
mainly happens to females. when they get out of the shower after washing their hair, and its still wet and they tie it up, then when it is dry they remove the hairtie and they are left with a big bump in their hair, which is hard to brush out.