complex and mysterious; complicated and inscrutable
Describes something that is not only intricate but also baffling or eerie in its complexity. Often used for situations, mechanisms, or plots that defy easy understanding.
Complex and mysterious circumstances are intertwined behind this case.
His explanation was so complicated and inscrutable that no one could understand it.
複雑 simply means 'complex' or 'intricate' without the added nuance of strangeness or mystery that 複雑奇怪 carries.
奇怪 means 'mysterious' or 'bizarre' on its own, but 複雑奇怪 emphasizes that the complexity itself is what makes it inscrutable.
Compound of 複雑 (complex) and 奇怪 (mysterious/bizarre). The exact historical derivation is uncertain, but the word is a straightforward combination of these two Sino-Japanese elements.