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dull (e.g. a knife); blunt
thickheaded; obtuse; stupid
dull (sound, color, etc.); dim (light)
slow; sluggish; inert; lethargic
insensitive; dull (e.g. reflexes); unperceptive; unfeeling
切れ味が悪くなったので鈍い包丁を砥石で研いだ。
The kitchen knife had become dull, so I sharpened it.
長年使った包丁の切れ味はかなり鈍かった。
The knife that had been used for years was quite dull.
この新しいナイフはまだ鈍くないはずだ。
This new knife shouldn't be dull yet.