gradually Antonyms

at once chop-chop in short order piercingly flat out like crazy like fun rapid transit meade midstream here and now observably hurriedly in an instant in a flash just then quickie avidly unhesitatingly suddenly unexpectedly against the clock asap all at once all of a sudden of a sudden surprisingly like a shot right away straight off straightaway simultaneously in no time slap bang pronto quick time straight away synchronously testily unmediated vociferously without delay with all speed in double quick time at the speed of light in a trice in less than no time in no time at all precipitously post haste