suppliciter
suppliciter is a Latin form of supplex, meaning “suppliant, begging; (noun) a suppliant”. It is the adverb.
Found 49 times in the Latin texts on Socratos.
Where it is used
Caesar, De Bello Gallico 1.27.2: Qui cum eum in itinere convenissent seque ad pedes proiecissent suppliciterque locuti flentes pacem petissent, atque eos in eo loco quo tum essent suum adventum expectare iussisset, paruerunt.
Ovid, Remedia amoris 640: Suppliciter dominae nomine dicat 'ave!'
All forms of supplex (declension table)
Source: Socratos (socratos.org), a free reader for Ancient Greek and Latin. Grammar from the Perseus Treebank and Morpheus; dictionary entries from Lewis & Short, A Latin Dictionary (Perseus Digital Library, CC BY-SA). Counts are from the texts on Socratos.