a.1.Sick as a dog sometimes is very sick.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
The humour may appeal to kids under eight but for the rest of us, watching Martin trying to get some laughs by merely shouting and falling over is as funny as treading in dogsick. Then there are such wondrous one-liners as, "It's not much, but I call it a second home", and "Every dad is entitled to one hideous shirt and one horrible sweater.