IUPAC name for citric acid
According to the current version of Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book), the order of seniority of classes in decreasing order of seniority is as follows.


  (…)
  7. acids
  (…)
  17. hydroxy compounds (includes alcohols and phenols)
  (…)


Thus, the carboxylic acid group has priority to be cited as a suffix.

Systematic names of carboxylic acids are generally formed using the suffix ‘oic acid’ or ‘carboxylic acid’ or the prefix ‘carboxy’.

The relevant rule in this case reads as follows:


  P-65.1.2.2.1 If an unbranched chain is linked to more than two carboxy groups, all
  carboxy groups are named from the parent hydride by substitutive use of the suffix
  ‘carboxylic acid’, preceded by the appropriate numerical prefix ‘tri’, ‘tetra’ etc. and
  appropriate locants.


Note that the suffix ‘carboxylic acid’ expresses the substituent group $\ce{-COOH}$. Thus, the name of unsubstituted tricarboxylic acid corresponding to the compound given in the question is ‘propane-1,2,3-tricarboxylic acid’.



Therefore, the preferred IUPAC name (PIN) of the complete compound given in the question is ‘2-hydroxypropane-1,2,3-tricarboxylic acid’.



However, according to Subsection P-65.1.1.2.3, the name ‘citric acid’ is also retained for general nomenclature.