unincisive
/ʌnɪnˈsɪsɪv/Definitions
1. adjective
Lacking in the quality of being incisive; not sharp or penetrating in thought or expression.
“Her unincisive arguments failed to convince the audience of her point.”
2. adjective
Not sharp or cutting; dull in thought or expression.
“The politician’s unincisive speech was a disappointment to his supporters.”