1570s, "the common people," from French vulgarité and directly from Late Latin vulgaritas "the multitude," from vulgaris (see vulgar). Meaning "coarseness, crudeness" is recorded from 1774.
"having a common measure" (as a yard and a foot, both of which may be measured by inches), 1550s, from Late Latin commensurabilis "having a common measure," from com "together, with" (see com-) + Latin mensurabilis "that can be measured," from mensurare "to measure," from Latin mensura "a measuring, a measurement; thing to measure by," from mensus, past participle of metiri "to measure," from PIE root *me- (2) "to measure."
"expression of approbation or esteem because of some virtue, performance, or quality," early 14c., from praise (v.). Not common until 16c.; the earlier noun, and the common one through most of the Middle English period, was praising (c. 1200).
Damn with faint praise, assent with civil leer,
And without sneering, teach the rest to sneer;
[Pope, "Epistle to Dr. Arbuthnot"]