而且
érqiě · HSK 2
and
➕ 而 = and/moreover + 且 = also; together: 'and also' = furthermore
而 is a classical connector meaning 'and/moreover', and 且 means 'also/further'. Stacking the two doubles down on the 'adding more' sense, giving 而且 = furthermore / and.
而 — pictograph of beard/whiskers hanging from chin
Originally a pictograph of a beard or facial hair hanging below the chin, visible clearly in oracle bone and bronze script forms. The beard meaning was lost early, and the character was borrowed phonetically to write the grammatical conjunction 'and/but/yet'. This connective use has been standard since classical Chinese.
且 — pictograph of an ancestral tablet or stacked offerings
且 originally depicted an ancestral spirit tablet or a stand holding ritual offerings, and it served as the early form of 祖 (ancestor). Over time it was borrowed to write the unrelated grammatical word meaning 'moreover' or 'and also,' so a new character 祖 was created for the original sense.