1.Definition: devoid of importance, meaning, or force

Related Adjective(s):unimportant

2.Definition: of little importance or influence or power; of minor status

"A minor, insignificant bureaucrat"

Related Adjective(s):peanut

3.Definition: signifying nothing

"Insignificant sounds"

4.Definition: small and unimpressive

"An insignificant sum of money"

Related Adjective(s):dinky