knows backwards and forwards (verb) know by heart: have absolute knowledge
Sinonime: amusing, aporetic,
arch, bantering,
derisive, disbelieving,
eccentric, incredulous, inquiring,
inquisitive,
mocking,
odd, probing,
quaint,
queer, questioning,
sardonic,
searching, show-me, skeptical,
supercilious, suspicious,
teasing, unbelieving,
unusualAntonime: certain,
understanding