vital, crucial, critical

basic, required, essential

odd, unusual

immense, vast, massive

obligatory, mandotory

immediate, abrupt

stable, fixed, consistent

numerous, plentiful, plenty

brilliant, breath taking, astonishing

fascinating, impressive, great

important , principal

primary, indispensable

bizarre, uncommon, peculiar

tremendous, gigantic, enormous

required, imperative

sudden, urgent

regular, constant

copious, abundant

picturesque, outstanding

alluring, charming

unusual, peculiar

immediate , near, close