- Cryptic - Hard to understand - Mysterious - Mysterious giant mice on the rampage - Mysterious little movement below coding machine - Perplexing - Puzzling
- Difficult or intricate - Difficult when gnarled - Gnarled - Hard to understand - Highly intricate part of Cork, not Tyrone! - Intricate, of a problem - Tangled
- Cloudy - Frosted (glass) - Hard to understand - Impenetrable to light - It’s hard to see though loop aqueduct section - Not transmitting light - Not transparent
- Abstruse - Arcane - Coteries in other places are difficult to understand - Coteries strange and hard to understand - Obscure: likely to be understood by a few only - Secret, mysterious - Designed for, and understood by, the specially initiated
alone; not communicated, or not intelligible, to the general body of
followers; private; interior; acroamatic; -- said of the private and
more recondite instructions and doctrines of philosophers. Opposed to
exoteric.
- Difficult to understand - Esoteric - Stubs are complicated and hard to understand - Concealed or hidden out of the way. - Remote from apprehension; difficult to be comprehended or
understood; recondite; as, abstruse learning.