I understand the term glass cannon but it seems like a lot of people in this thread are equating shot chin as glass cannon, two examples I see mentioned multiple times are Manhoef and Overeem.
Manhoef: 47 MMA fights, 5 KO losses to Carvahlo, Schilling, Lawler, Glunder, Schrijber. Losing by KO to any of those fighters does not mean you have a glass chin.
Overeem: 62 fights, 13 KO losses BUT prior to fighting in the UFC 47 fights, 5 KO losses and one corner stoppage, KO losses to Shogun 2 times, Chuck, KharinotovOvnd Hoffman early in his career. None of these losses would mean your a glass cannon. He entered the UFC after this and his K-1 career as well.
Factor in their kickboxing careers and one can come to the conclusion they are shopworn. Why are they glass cannons but Chuck Liddell gets a pass?