Unfeeling; pitiless; callous.
Inured; toughened.
Firmly established or unlikely to change; inveterate.
Having extra defences against attack; highly fortified.
unvoiced; voiceless
Involving surds, or irrational numbers; not capable of being expressed in rational numbers.
An irrational number, especially one expressed using the √ symbol.
A voiceless consonant.