Word: unbeknownst
Part of speech: Adverb
Syllables: un
be
knownst
Definition: without the knowledge of
Morphemes:
Affix: un-
Language: en
PoS: Prefix
Meaning: absent; lacking; not; negative
Affix: be-
Language: en
PoS: Prefix
Meaning: All around; about; abundantly; all over.
Affix: known
Language: en
PoS: Verb
Meaning: Alternative form of know; the fact of being aware of information that is known to few people
Affix: -st
Language: en
PoS: Suffix
Meaning: Verb suffix for the second-person singular; alternative form of "-est".