Meaning

noun a low bed to be slid under a higher bed

verb yield to out of weakness

verb try to gain favor by cringing or flattering

originFrom a back formation of truckle bed (a bed on which a pupil slept, because it was rolled on casters into a lower position under the master's larger bed), from Middle English trookylbed. Compare also trundle bed. Assisted by false association with Middle English *trukelen, truken, trokien, trukien, from Old English trucian (“to fail, diminish”), Low German truggeln (“to flatter, fawn”), see truck.

Etymology from Wiktionary, CC BY-SA 3.0