lad vs laddie

lad and laddie both are nouns.

Word	Noun	Adjective	Verb	Adverb
lad	Yes	No	No	No
laddie	Yes	No	No	No

As nouns, lad and laddie are synonyms defined as:

Other synonyms of lad include cub, sonny, sonny boy.

lad (noun)	laddie (noun)
a male child (a familiar term of address to a boy)	a male child (a familiar term of address to a boy)
a boy or man