にぶ鈍nibuるruなま鈍namaるru
1.
To lose sharpness or effectiveness over time, often referring to tools or skills that no longer function as well as they once did due to lack of use or practice.
2.
To experience a decline in vigor or intensity, such as a decrease in enthusiasm, determination, or physical ability, often as a result of aging or inactivity.
3.
To have a reduced responsiveness in mental or sensory functions, indicating a slowdown in cognitive or perceptual abilities, commonly due to factors like insufficient training or old age.
Example:
テレビは創造力を鈍らせる力がある。