Depending on context, "dull" can mean bland, stale, tired, banal, ho-hum, murky, muted, faded, muddy, dingy, quiet, faint, blunt, dense, thick, dopey, weary
Sharp
dull
drab
edgeless
Brightest
insipid
blah
brilliant.
tritest
throb
A five letter word for bravery is valor.
Scarf is a five letter word for muffler.