Informed

google

ref

Middle English enforme, informe ‘give form or shape to’, also ‘form the mind of, teach’, from Old French enfourmer, from Latin informare ‘shape, fashion, describe’, from in- ‘into’ + forma ‘a form’.

wiktionary

ref

inform +‎  -ed

in- +‎  formed the first sense probably uses  in-(“in”), the second sense uses  in-(“prefix of negation”). 

etymonline

ref

informed (adj.)

1540s, "current in information," past-participle adjective from inform (v.). In 16c.-17c. it also could mean "unformed, formless," from in- (1) "not, opposite of," and was used in astronomy of stars that did not form part of the visual pattern of a constellation but were within it.