1. 18 Frighten or surprise one and it will stiffen and keel over in what appears to be a dead faint.

2. 28 O'B: Because complicated applications crash, or get abandoned by their creators,[www.Sentencedict.com] or just keel over from feature-bloat and become unusable around version 0.

3. Verb overturn, turn over, invert, tip over, keel over, turn turtle, upset The sea got very rough and the boat Capsized. Collins Thesaurus of the English Language – Complete and Unabridged 2nd Edition