Having no variations in height. • In a horizontal line or plane; not sloping. • Smooth; having no protrusions, indentations or other surface irregularities, or relatively so. • Having small or invisible breasts and/or buttocks. • Without variation in level, quantity, value, tone etc. • At a consistently depressed level; consistently lacklustre. • Of fees, fares etc., fixed; unvarying. • Without variations in pitch. • Not diphthongal; without variation in height or backness. • Without variation in tone or hue (uniform), and dull (not glossy). • Lacking liveliness or action; depressed; uninteresting; dull and boring. • Lacking in depth, substance, or believability; underdeveloped; one-dimensional. • Lowered by one semitone. • Of a note or voice, lower in pitch than it should be. • Absolute; downright; peremptory. • Deflated, especially because of a puncture. • With all or most of its carbon dioxide having come out of solution so that the drink no longer fizzes or contains any bubbles. • Lacking acidity without being sweet. • Unable to emit power; dead. • Without spin; spinless. • Sonant; vocal, as distinguished from a sharp (non-sonant) consonant. • Not having an inflectional ending or sign, such as a noun used as an adjective, or an adjective as an adverb, without the addition of a formative suffix; or an infinitive without the sign "to". • Having a head at a very obtuse angle to the shaft. • Flattening at the ends. • Exact. • Such that the tensor product preserves exact sequences. See Flat module on Wikipedia.Wikipedia. • Such that its target, regarded as a module over its source, is flat (as above). • Such that the induced map on every stalk is flat (as a map of rings). • Having little froth and little milk. • Foolish; simple-minded.