Laudator Temporis Acti

The Concise Oxford Dictionary of English Etymology, s.v. pity:

ME. pite — OF. pité (mod. pitié):— L. pietās, -tāt- PIETY. In later L. pietās acquired the sense of compassion, kindness; OF. pite and piete had both senses, but were subsequently differentiated, and this was reflected in the corr. Eng. forms as now used.

The sense "compassion, kindness" can also be seen in earlier Latin, according to Nisbet and Rudd in their commentary on Horace, Odes 3.21.4 (pia testa):

The adjective here means, not 'devout' (which does not suit a deity), but 'kindly', 'loving', 'caring' (qualities that reciprocate human devotion). For this rare usage cf. Virg. Aen. 2.536 'di, si qua est caelo pietas quae talia curet' with Austin's note, 4.382 with Pease, 5.688 f. (addressed to Jupiter) 'si quid pietas antiqua labores / respicit humanos', Martial II.3.9 'cum pia reddiderint Augustum numina terris', Weinstock 249 (citing Oscan material), RE 20.1.1180, Encicl. virg. 4.95. This is the meaning of pie Jesu, and pietas in this sense has given rise to the English 'pity'.

Labels: etymology