unidirectional (adj.)

• direct
• immediate
• irreversible
• one-piece
• one-sided
• one-way
• straight
• straightaway
• straightforward
• unbroken
• undeviating
• unicameral
• unicellular
• unicuspid
• unidimensional
• unifoliate
• unilateral
• uninterrupted
• unipolar
• univalent
• univocal
• unswerving