formidable – грозный, внушительный, огромный, значительный, труднопреодолимый
www.ldoceonline.com/dictionary/formidable
1 very powerful or impressive, and often frightening
2 difficult to deal with and needing a lot of effort or skill
// “…though it looks formidable in the beginning, it’s not so difficult to achieve results and to get people Realised.” (1988/07/28)
// “And we have formidable job…” (1989/05/24)
youglish.com/pronounce/formidable/english/us?
formidable