to praise to a lesser degree or extent than the circumstances warrant
Word origin
[1690–1700; under- + praise]This word is first recorded in the period 1690–1700. Other words that entered Englishat around the same time include: catamaran, foolscap, lifeline, momentum, smashunder- is a prefixal use of under, as to indicate place or situation below or beneath (underbrush; undertow); lower in grade or dignity (undersheriff; understudy); of lesser degree, extent, or amount (undersized); or insufficiency (underfeed)