nerveless
1. [ adjective ] marked by calm self-control (especially in trying circumstances); unemotional
Synonyms: cool coolheaded
Examples:

"play it cool" "keep cool" "stayed coolheaded in the crisis" "the most nerveless winner in the history of the tournament"

Related terms: composed
2. [ adjective ] lacking strength
Synonyms: feeble
Examples:

"a weak, nerveless fool, devoid of energy and promptitude"- Nathaniel Hawthorne

Related terms: powerless
Similar spelling:   nervelessly
  nervily