advise
advisory
alarm
alert
announce
caution
clipart
command
constraint
counsel
curb
danger
dangerous
dumping
forbid
foreboding
forewarning
garbage
harm
illegal
illustrate
illustration
info
informative
kills
limitation
no
placard
pollute
pollution
post
prohibition
recommend
recommendation
red
restrict
restriction
rule
sign
signal
stop
symbol
tell
trash
violators will be prosecuted
warning