noun

• (uncountable) The quality or state of being fast (in various senses).
• The quality or state of being strongly attached; firmness, secureness, tenacity.
• (specifically) The ability of a dye to withstand fading.
• The quality or state of moving quickly; quickness, rapidity, swiftness.
• The quality or state of having an extravagant lifestyle or immoral habits.
• (archaic) Of a fortress or other place: the quality or state of being secure from access or attack; safety, security.
• (obsolete) The quality or state of being firm, hard, or solid; firmness, hardness, solidity.
• (countable) Something that is fast, or that causes someone or something to be fast (in various senses).
• (also figuratively) A fortified or secure place; a fortress, a stronghold.
• (obsolete except Britain, regional) Something used to fasten or tie; a fastener or fastening.