1.Someone who got his achille'
s heel
cut.
2.When you are about to say something very
crucial in an important discussion and suddenly someone makes a totally ridiculous comment in order to produce laughter, feeling the matter is too hard to be sustained.
1.I saw an opening in Broderick the Morög'
s armor; but as I was about to thrust my spear into his sinews, Fegellahar the Small attacked me traitorously; I was hamstrung, almost fainting with pain.
2.I was about to explain to the engineers the crucial relationship between
plastic fabrication and beezwax, but Roger boasted this ludicrious
joke about vaseline; I was hamstrung.