"nerveless" in the adjective sense
1. cool, coolheaded, nerveless
marked by calm self-control (especially in trying circumstances unemotional
"play it cool"
"keep cool"
"stayed coolheaded in the crisis"
"the most nerveless winner in the history of the tournament"
2. feeble, nerveless
lacking strength
"a weak, nerveless fool, devoid of energy and promptitude"- Nathaniel Hawthorne
Source: WordNet® (An amazing lexical database of English)
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