mancub Share definition Flag a man who is at least 7 years younger than the person he is dating and or engaging in a relationship. "I'm 33 and I am dating a 24 yr. old. I call him my mancub." mancub by 1brazilnut January 13, 2008 0 0 Get merch Get the mancub mug. Buy Now — $32.95 See more merch