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When a friend asks you how big your ex-girlfriends boobs were, but you say they we're one size larger.

Idiot 1: They we're Z cups Dude!
Idiot 2: O.... M.... G!
"Brandon always Overchestimates his ex-girlfriends; That guy is an idiot."
by Tower defense February 03, 2010

Words related to Overchestimate

boobs chestimate
To guess a girls breastsize only to find later that the extra cup size came with the bra...
I totally overchestimated Alli... She looked to be a solid B, only to find out she was barely an A!
by Koition February 05, 2010