- simplex - allowing communication in only one direction at a time, or in telegraphy allowing only one message over a line at a time; "simplex system"
Antonym: bidirectional (indirect, via unidirectional)
- simplex - having only one part or element; "a simplex word has no affixes and is not part of a compound--like `boy' compared with `boyish' or `house' compared with `houseboat'"
Antonym: complex (indirect, via simple)