Bohemian
affable
airy
blase
breezy
careless
casual
common
cordial
cursory
devil-may-care
disregardant
disregardful
easy
easygoing
familiar
flippant
folksy
forgetful
free and easy
gracious
haymish
heedless
homely
homey
inconsiderate
indifferent
informal
insouciant
irregular
lackadaisical
lazy
loose
low-pressure
natural
nonchalant
oblivious
offhand
offhanded
perfunctory
plain
reckless
regardless
relaxed
respectless
simple
sociable
tactless
thoughtless
unaffected