Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pī̆grĕo, ēre, v. n. [piger], to be slow, sluggish, reluctant (ante-class.): post aetate pigret sufferre laborem, Enn. ap. Non. 219, 12 (Ann. v. 405 Vahl.): omnes gaudent facere recte, male pigrent, Att. ap. Non. 14.
pī̆gro, āvi, ātum, 1, v. n. [piger], to be indolent, slow, dilatory (ante-class.), Lucr. 1, 410: melius pigrasse quam properasse est hoc nefas, Att. ap. Non. 154, 2 (Trag. Rel. p. 144 Rib.): cur propter haec pigrem? id. ib. 153, 32 (Trag. Rel. p. 147 Rib.).