na-adjective, noun which may take the genitive case particle 'no', noun
weak-kneed; timid; lacking firmness
Describes a person, attitude, or stance that is irresolute, easily yielding, or lacking backbone, especially in negotiations or confrontations.
You must not show a weak-kneed attitude in negotiations.
彼の弱腰な発言に失望した。
I was disappointed by his timid remarks.
He suddenly became timid once the negotiations started.
The government was criticized for taking a weak-kneed stance toward the neighboring country.
The prime minister was criticized by the opposition for his weak-kneed attitude.
The company responded to the complaint in a weak, yielding manner.