adverb
Etymology: Middle English familierly, from familier, adjective + -ly — more at familiar II
1. : in a familiar manner: as
a. : intimately
he was widely known to many but familiarly acquainted with few
b. : commonly
the frankfurter is familiarly called a hot dog
c. : informally
hailed him familiarly by his nickname
d. : presumptuously
pinched her cheek familiarly when they were introduced
2. : without shyness or fear : boldy
the phoebe bird … comes familiarly about the house — John Burroughs