IPA: /ˈheɪstɪnəs/
KK: /ˈhæs.tɪ.nəs/
The quality of doing things too quickly without thinking carefully.
His hastiness in making decisions often led to mistakes.
Hastiness → It is formed from "haste" (from Old French *hastier*, meaning to hurry) and the suffix "-ness" (meaning the state or quality of). The word "hastiness" refers to the quality of being hurried or acting quickly without careful thought.
Think of 'haste' as being in a hurry, and remember that 'hastiness' means the quality of acting quickly, often without thinking.