Synonyms of DEEP

a long steep-sided depression in the ocean floor

• TRENCH11

Also: oceanic abyss.

having or denoting a low vocal or instrumental range

• BASS6

strong; intense

• RICH9

(of darkness) very intense

• THICK14

of an obscure nature

• CRYPTIC16
• CRYPTICAL18
• INSCRUTABLE15
• MYSTERIOUS15
• MYSTIFYING22

difficult to penetrate; incomprehensible to one of ordinary understanding or knowledge

• ABSTRUSE10
• RECONDITE12

to a great depth; far down

• DEEPLY12

to an advanced time

• LATE4