by-line vs pastime

by-line and pastime both are nouns.

Word	Noun	Adjective	Verb	Adverb
by-line	Yes	No	No	No
pastime	Yes	No	No	No

As nouns, pastime is a hypernym of by-line; that is, pastime is a word with a broader meaning than by-line:

by-line: an auxiliary activity
pastime: a diversion that occupies one's time and thoughts (usually pleasantly)

Other hypernyms of by-line include interest, pursuit.

by-line (noun)	pastime (noun)
an auxiliary activity	a diversion that occupies one's time and thoughts (usually pleasantly)
a line giving the name of the writer of a story or article