"feebleness" in the noun sense
1. infirmity, frailty, debility, feebleness, frailness, valetudinarianism
the state of being weak in health or body (especially from old age)
2. feebleness, tenuity
the quality of lacking intensity or substance
"a shrill yet sweet tenuity of voice"- Nathaniel Hawthorne
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License