I suppose you could devise something including length of grass, moisture content, pressure needed to apply to depress surface by n mm, a shear test could be devised, imitating say a 12 stone man sliding for 1 meter at 5 kph. That’s just me making something up.
You could look at rye EFL rules, which say:-
28 Playing Surface Standard / Slope of Pitch
28.1 The playing surface shall be grass and must be of a high standard, as defined by The Football League.
28.2 It must be flat and free from surface depressions and excessive undulations.
28.3 The maximum slopes allowable shall not exceed an even gradient of vertical to horizontal 1:41 in any direction.
28.4 Each Home Club shall provide full pitch frost covers and/or under soil heating (the specification of which shall meet the reasonable satisfaction of the Executive) which shall be operated to the extent necessary to procure, so far as it is reasonably possible, that the pitch is playable on the occasion of each match. A breach of this requirement which results in the postponement or abandonment of a match shall be dealt with in accordance with Regulation 28, and not Regulation 8.4.
Unfortunately I haven’t been able to find a written definition as referred to in 28.1
Or you could rely on an expert or experienced person, say a referee. The range of acceptability from such a person is likely to be relatively narrow
I’m pretty sure experienced groundsmen know what is likely to be acceptable to a referee. In any event, the state of the pitch at 6pm yesterday was very far from what would be acceptable on a council pitch, let alone for professional sport