The OED says that the noun give derives from the verb, and means:
The action, fact, or quality of ‘giving’ (cf. sense 40 of the vb.); a yielding, giving way.
And where the referenced sense 40 is:
40. intr. To yield, give way.
a. To yield to pressure or strain.
b. Of a joint, the nerves: To lose tension, to become relaxed, to fail.
c. (Of persons): To accommodate one’s attitude to; (of a dress) to adjust itself to (the varying curves of the figure). Also, to allow free play, yield to. Also, to give ground, draw back.
d. To be affected by atmospheric influences;
- (a).of colours, to fade;
- (b).to deliquesce, effloresce, soften, or deteriorate, from the effect of damp;
- (c).to become damp, (appear to) exude moisture, as a stone floor after a thaw (see eve v.2);
- (d).of timber, to shrink from dryness.
e. Of frosty weather: To relax its severity, to become mild; to thaw.
f. what gives?: what is happening? (freq. as a question or merely as a form of greeting); so what gives with (someone or something)? = what is happening to?; what is (he, etc.) doing? (Cf. G. was gibt’s?) colloq. (orig. U.S.).
You probably should not consider Etymonline, which is mostly just cribbed from the OED anyway, to be a one-stop shopping center for these researches.