Lock is a synonym of quiff.
As a proper noun lock
As a noun quiff is
a puff or whiff, especially of tobacco smoke or quiff
can be (regional|slang) a trick or ploy; a stratagem or quiff
can be a hairstyle whereby the forelock is brushed and/or gelled upward, often associated with the styles of the 1950s or quiff
can be (slang) a young girl, especially as promiscuous; a prostitute.
As a verb quiff is
to arrange (the hair) in such a manner.