Consigliori means advisor and that person is the right hand of The Don in italian Mafia-families.
From The Godfather:
The other Mafia families disliked the fact that the Corleones had a german-irish Consigliori. Because of Tom Hagen, the Corleones were sometimes referred to as "The Irish Gang".
Most commonly pronounced "Coon-seal-ea-air-ee". Basically mean a councelor in Italian. Most commonly known from the Mafia as a high ranking Made Man. In the Mafia his job is to counsil and advise the boss, sometimes known in the media as the Don on any big decisions. Despite the Godfather consigliori is a rank just below the "caporgimes" and there never has been a non Italian consigliore.
"Consigliori, what do you think about these plans?" "I think its dangerous but needs to be taken care of"