say it: FAWR-thwith
forthwith is an adverb meaning "without delay or hesitation; with no time intervening". It carries one recorded sense.
without delay or hesitation; with no time intervening
“he answered immediately”
“found an answer straightaway”
“an official accused of dishonesty should be suspended forthwith”
“Come here now!”
Definitions, synonyms and semantic relations for forthwith come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.