Grammatical? omission-cum, action-sans

I came across this on Quora, but no answer there. I know cum in this sense is "combined" or "with" (from the Latin for "with"). sans is French word for ‘without’ in English. Decina is a New York law case, but I don't know law or philosophy.

How's bold sentence grammatical? Authors are professors and look very educated! I don't think they are bad grammar. Michael S. Moore

JD, SJD Harvard University
AB University of Oregon

Heidi Hurd

JD, PhD University of Southern California
MA Dalhousie University
M.E.M. School of Forestry and Environmental Studies, Yale University
BA Queen’s University

Punishing the Awkward, the Stupid, the Weak, and the Selfish: The Culpability of Negligence Crim Law and Philos (2011) 5:147–198. DOI 10.1007/s11572-011-9114-0.

      The argument for liability for inadvertent harm causing stemming from the existence of these two kinds of precautionary acts is a Decina-like argument, albeit based on earlier omissions that fail to prevent harms rather than on earlier actions that positively cause harms. The argument is that culpability in such cases is premised on the chosen omission to take precautions against the harmful effects of flaws the actor knew she possessed. [1] The earlier omission-cum awareness replaces the later action-sans awareness as the theory of liability in such cases.

I try replace "cum" and "sans" with English.

[2] The earlier omission-WITH awareness replaces the later action-WITHOUT awareness as the theory of liability in such cases.

2 is not grammatical. omission-WITH and action-WITHOUT just weird!

Latin terms often incorporate legal concepts and Latin phrases or phrases that include Latin are often set phrases with a specialist meaning.

Based on what knowledge I have of English law, rather than American, "omission-cum" and "action-sans" are noun phrases used attributively describing forms of negligent action.

(I base this on an American legal concept "Simul cum" (Latin) (See the entry The Free Dictionary) https://legal-dictionary.thefreedictionary.com/Simul+cum

3. When a party sued with another pleads separately, the plea is generally entitled in the name of the person pleading, adding "sued with___," naming the other party. When this occurred, it was, in the old phraseology, called pleading with a simul cum.)

"Omission-cum" can be understood as "including an omission" and "action sans" can be understood as excluding an action.

The troublesome word is "awareness" - in this context it seems to mean "what was in the person’s mind at the time” (The person was or should have been aware of something.)

omission-cum awareness = the state of mind that knew that failing to do something would cause harm.

Action-sans awareness = the state of mind of doing something that he failed to realise would cause harm.