safety margin vs margin of safety

safety margin and margin of safety both are nouns.

Word	Noun	Adjective	Verb	Adverb
safety margin	Yes	No	No	No
margin of safety	Yes	No	No	No

As nouns, safety margin and margin of safety are synonyms defined as:

safety margin and margin of safety: the margin required in order to insure safety

Other synonyms of safety margin include margin of error.

safety margin (noun)	margin of safety (noun)
the margin required in order to insure safety	the margin required in order to insure safety