DECL LIKE ADJ is in English.  It is an abbreviation for
DELINE LIKE ADJECTIVE.  The word Dezhurnaya is adjective,
but in Russian it can be used in place of the proper noun
"Dezhurnaya Zhenschina" -- almost like a pronoun.

My best guess is that the hotel had asked a native Russian 
speaker to translate the hotel signs into English.  Because 
the position of a Dezhurnaya is a Russian concept, the translator
was probably unsure how to translate it into English.  So, 
he must have used a dictionary. In many dictionaries, Russian
adjectives that act as pronouns are usually identified by 
reminding the dictionary user to "Decline the word like an 
adjective" or to remember to use the word as an adjective, 
not a noun.  But instead of writing the entire phrase, it 
was abbreviated in normal dictionary fashion:  "DECL LIKE ADJ"
The translator probably assumed that this phrase was the
definition, and had the hotel place this phrase on each sign
in the hotel.