SIDS vs infant death

SIDS and infant death both are nouns.

Word	Noun	Adjective	Verb	Adverb
SIDS	Yes	No	No	No
infant death	Yes	No	No	No

As nouns, SIDS and infant death are synonyms defined as:

SIDS and infant death: sudden and unexpected death of an apparently healthy infant during sleep

Other synonyms of SIDS include cot death, crib death, sudden infant death syndrome.

SIDS (noun)	infant death (noun)
sudden and unexpected death of an apparently healthy infant during sleep	sudden and unexpected death of an apparently healthy infant during sleep