morale booster vs morale building

morale booster and morale building both are nouns.

Word	Noun	Adjective	Verb	Adverb
morale booster	Yes	No	No	No
morale building	Yes	No	No	No

As nouns, morale booster and morale building are synonyms defined as:

morale booster and morale building: anything that serves to increase morale

Other synonyms of morale booster include morale builder.

morale booster (noun)	morale building (noun)
anything that serves to increase morale	anything that serves to increase morale