steely 
/ˈsti:li/ adjective
steel·i·er; steel·i·est /ˈsti:li/ adjective 1 : very strong and determined often in a cold or unfriendly way
▪ a thief with steely nerves ▪ He had a steely determination to succeed. ▪ She gave him a steely gaze. 2 : resembling steel especially in color
▪ a sky filled with steely gray clouds ▪ the judge's steely blue eyes
▪ a thief with steely nerves ▪ He had a steely determination to succeed. ▪ She gave him a steely gaze.
▪ a sky filled with steely gray clouds ▪ the judge's steely blue eyes
