suitably (adverb) describes the verb 'impressed'... suitable is the adjective So, suitably tells us 'how much/to what extend or degree' was someone impressed. Synonyms of 'suitably' include: sufficiently abundantly acceptably appropriately fairly well fittingly modestly pleasantly enough satisfactorily sufficiently to an acceptable degree well enough Suitably impressed means impressed enough / quite impressed / very impressed / completely impressed. For example: The exam was very difficult and Tom was pleasantly surprised when he learned that he got a very high mark. So, Tom was 'suitably impressed' was his high mark, and when he told me his mark/score, I was also suitably impressed.