squeaky wheel

Etymology
From the proverb "the squeaky wheel gets the grease"/oil.

Noun

 * 1) A complainer; one who speaks out when there are problems.
 * 2) Of several problems, the most apparent or the most urgent.
 * 1) Of several problems, the most apparent or the most urgent.

Synonyms

 * See also Thesaurus:complainer
 * See also Thesaurus:complainer
 * See also Thesaurus:complainer
 * See also Thesaurus:complainer