to cause (a person, achievement etc) to seem unimportant or of small value

detract

to say that one is not satisfied, that something is wrong, that one is suffering

grumble about

to you say that (a person) is, or has done wrong or that (something) is wrong or unfit for use

blame, convict

to express great approval of, show one is very sorry about, (something)

regret; condemn

to have, express, an unfavourable opinion

condemn

to say that one does not own for have a connection with (a person, thing, action etc)

deny

(to try) to take away the courage or confidence of (a person)

dishearten, dispirit

to advise a person against (doing something)

talk out of

to reduce (something) to the smallest amount or degree

make smaller; underrate

to make a protest; argue in protest

argue against

to have too low an estimate or opinion of (a person, ability etc)

minimize; rate too low

to inform (a person) of possible danger or unpleasant consequences

give notice of possible occurrence