-n't shortened (enclitic) form of not¹

NT

1. National Theatre (now known as RNT)
2. National Trust
3. New Testament
4. Northern Territory (Aust)
5. Northwest Territories (of Canada)
6. No trumps (cards)

• subers
• subfactorial
• subfactorials
• subfamilies
• subfamily
• subfertile
• subfertilities
• subfertility
• subfeu
• subfeudation
• subfeudations
• subfeudatory
• subfeued
• subfeuing
• subfeus
• subfield
• subfields
• subfloor
• subfloors
• subframe
• subframes
• subfreezing
• subfusc
• subfuscous
• subfuscs