lecture (noun) lecture: lesson, speech
Sinonime: baffling,
difficult,
impenetrable, indecipherable,
inexplicable, inextricable, irresolvable, mystifying,
obscure, unaccountable, unconcluded,
unfathomable, unresolved, unsolvable, unsolved
Antonime: explainable, explicable,
obvious,
open, solvable