deprecate
verb (used with object)
to express earnest disapproval of.
Used to describe an ongoing action or state that is currently taking place in the immediate present.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
But his reply in that case is deprecating, implying that he doesn't think very much of him, do you? which is intended to draw further reassurance and compliment.
From War-time Silhouettes by Stephen Hudson