Whence H. P. Grice took 'helpfulness'

ad-iuvō iūvī  (adiuerō, old for adiūverō), iūtus, āre, to help, assist, aid, support, further, sustain: fortīs fortuna adiuvat, T.: maerorem orationis meae lacrimis suis: suā sponte eos, N.: pennis adiutus amoris, O.: in his causis: alqm ad percipiendam virtutem: si quid te adiuero, poet ap. C.: ut alqd consequamur, adiuvisti: multum eorum opinionem adiuvabat, quod, etc., Cs.—With ellips. of obj, to be of assistance, help: ad verum probandum: non multum, Cs.: quam ad rem humilitas adiuvat, is convenient, Cs.—Supin. acc.: Nectanebin adiutum profectus, N.—P. pass.: adiutus a Demosthene, N.—Fig.: clamore militem, cheer, L.: adiuvat hoc quoque, this too is useful, H.: curā adiuvat illam (formam), sets off his beauty, O.