instant (adjective) instant: immediate, urgent
Sinonime: approximate, capricious, discretionary,
erratic,
fanciful,
frivolous,
inconsistent, injudicious,
irrational,
irresponsible, offhand, optional,
random,
subjective,
supercilious,
superficial, unaccountable,
unreasonable, unscientific,
wayward, willful
Antonime: circumspect,
rational,
reasonable, reasoned,
supported