Found in the following dictionaries
SOWPODS (Collins Scrabble Words)
"Yus" Definition
adverb
Dialectual form of yes.
Source: Wiktionary
unknown
Either of two letters, little yus (Ѧ) and big yus (Ѫ), representing nasal vowel sounds in the Cyrillic alphabet. The only Slavic language retaining these sounds is Polish, which is written in the Latin alphabet. Modern languages thus have little yus for them.
Source: Wiktionary