unvigilant
/ʌnˈvɪdʒɪlənt/Definitions
1. adjective
Lacking the quality of being watchful or attentive; careless or inattentive
“The unvigilant driver failed to notice the pedestrian crossing the road.”
2. noun
A person who is unvigilant or careless
“The company’s unvigilant management led to a series of financial scandals.”