Answer:

bub

Answer	Crossword Clue
BUB	Mac
BUB	"Mac"
BUB	Fella

BUB	Impolite alternative to "sir"
BUB	Buddy
BUB	Buster
BUB	Bro
BUB	Chum
BUB	Fellow
BUB	Dude
BUB	Frequently insolent alternative to "sir"

BUB	"My Three Sons" role
BUB	Address to a fella
BUB	Pal
BUB	Insolent appellation
BUB	Small boy.
BUB	Brother.
BUB	Little fellow.
BUB	Familiar word of address.

BUB	Relative of Mac or pal
BUB	Sonny
BUB	Any old Joe
BUB	"Hey, .....!" ("Hey, fella!")
BUB	Buster or fella
BUB	"Mac" alternative
BUB	Kin of "mac"
BUB	"Hey, ...!" ("Hey, fella!")

BUB	Fella relative
BUB	Howdy, ...!: pal
BUB	Kiddo
BUB	Buster, mac or fella
BUB	Condescending term of address
BUB	Mac alternative