suddenly (adv.)
- aback
- abruptly
- bang
- dash
- feverishly
- forthwith
- hastily
- headfirst
- headlong
- hurriedly
- impetuously
- implausibly
- improbably
- impulsively
- instantaneously
- instantly
- momentarily
- plop
- plump
- plunk
- pop
- precipitately
- precipitously
- quickly
- rapidly
- rashly
- recklessly
- sharp
- short
- slap
- slap-bang
- smack
- speedily
- startlingly
- sudden
- surprisingly
- swiftly
- unawares
- unexpectedly
- unpredictably
