defeating
de-feat-ing
verb
The action of overcoming an opponent, problem, or preventing something from succeeding.
"They are defeating the opposition easily."
adjective
Causing a feeling of hopelessness, overwhelming frustration, or a sense of being beaten.
"The sheer volume of work felt utterly defeating."
Thesaurus
Synonyms: defeat, get the better of, overcome, frustration, vote down, vote out, kill, shoot down, licking