furlough vs give the sack

furlough is a noun but give the sack is not a noun.

Word	Noun	Adjective	Verb	Adverb
furlough	Yes	No	Yes	No
give the sack	No	No	Yes	No

As verbs, give the sack is a hypernym of furlough; that is, give the sack is a word with a broader meaning than furlough:

furlough: dismiss, usually for economic reasons
give the sack: terminate the employment of; discharge from an office or position

Other hypernyms of furlough include can, dismiss, displace, fire, force out, give notice, give the axe, sack, send away, terminate.

furlough (noun)	give the sack (noun)
a temporary leave of absence from military duty

furlough (verb)	give the sack (verb)
grant a leave to	terminate the employment of; discharge from an office or position
dismiss, usually for economic reasons