1. Incapable of being perceived or known
   - incognizable, incognisable [Brit]

See also: imperceptible, unperceivable

• alpha-interferon
• alpha-linolenic acid
• alpha-lipoprotein
• alpha-naphthol
• alpha-naphthol test
• alpha-tocopheral
• alphabet
• alphabet soup
• alphabetic
• alphabetic character
• alphabetic script
• alphabetic writing
• alphabetical
• alphabetically
• alphabetisation
• alphabetise
• alphabetised
• alphabetiser
• alphabetization
• alphabetize
• alphabetized
• alphabetizer
• alphameric
• alphamerical
• alphanumeric