tongue-tie

Short definition from Wiktionary

Noun

1. 1
   Ankyloglossia, a congenital oral anomaly.
2. 2
   A piece of cloth used to tie down a horse's tongue, to facilitate breathing etc.
3. 3
   Alternative form of tongue-tie.

Verb

1. 1
   To disconcert or fluster (a person) so that they cannot speak coherently.