acute
alert
area
arrest
barbed
barrier
blue
boundary
chop
close
cloud
colony
construction
cut
danger
denied
failure
fence
grid
guard
hard
illegal
industrial
international
migrant
pressure
prickly
problem
prohibition
protect
protection
punish
punishment
refuse
ring
safe
safety
secret
security
sky
stop
symbol
syria
tenon
thorn
warning
white
wire