1. Of, pertaining to, or having dyspepsia (indigestion).
2. Irritable or ill-humored, as if suffering from dyspepsia; morose; gloomy.
1. A person suffering from dyspepsia.
"Is that dyspeptic man scowling because his life tastes sour or because he didn't want his picture taken?"-- Jake Miller, "Faces Without Lives", New York Times, March 28, 1999
"Wild joy, gaiety, sensual pleasure, disregard of all sad or even sensible feelings reached such a pitch . . . that instances have been cited of old millionaire merchants, old usurers, old notaries who, during this interval, had forgotten to be dyspeptic and obsessed with making money."--Stendhal, The Charterhouse of Parma (translated by Richard Howard)
"So how did English food acquire the reputation of nursery food for adults with dyspeptic stomachs?"-- Nadine Brozan, review of Seven Centuries of English Cooking, by Maxime de la Falaise, New York Times, December 16, 1992
Dyspeptic is derived from Greek dys-, "difficult, bad" + pepsis, "digestion." The opposite of dyspeptic is eupeptic, "having good digestion; also, cheerful."
--Dictionary.com Entry and Pronunciation for dyspeptic
It may surprise the reader to learn that I have included dyspeptic in "Words Worthy" precisely because in certain social circumstances it can prove to be usefully vague.
You can see from the two definitions above that the word can mean
(1) indigestion or
(2) feeling morose, gloomy, irritable, or ill-humored, as if suffering from dyspepsia. [I highlighted "as if" because you don't have to have indigestion per se in order to feel irritable or ill-humored.]
Some day, when you return to work after being sick, you may find the resident quid nunc asking about your absence. You could say simply, "I was feeling dyspeptic," and your snoopy interlocuter will be none the wiser, for "feeling dyspeptic" can mean either (1) you simply felt ill-disposed or (2) you were suffering discomfort in your digestive tract--which could involve anything from heartburn to irritated bowel syndrome to any one of several intestinal problems.
If, at another time, you are in a conversation with a medical professional in which you suggest that you think you are suffering from dyspepsia, the use of dyspepsia will serve as a useful conversation starter because it has located the part of your body that is in distress: your digestive tract. The next step is to probe beyond the generalized term dyspepsia to identify and then cure you of the problematic ailment, which will have another name, such acid stomach reflux, GERD, or any of a number of ailments: "cachexy, cachexia, atrophy, marasmus, consumption, palsy, paralysis, or prostration."--adapted from Roget's Thesaurus.
So how can using the word dyspeptic prove to be useful precisely because it is vague? The answer is because by using it you are telling a quizical person in a genteel way that you have been ill and that's all you want to say about it. You could could bring such a conversation to a close by saying "I was dealing with a touch of dyspepsia yesterday, but today I feel rested, reenergized, and--in a word--eupeptic! See you later."