Interestingly, hagiazō is only translated as "holy" here in the KJV: elsewhere out of 29 total KJV Occurrences, it is,
sanctified, 16
Joh_10:36, Joh_17:19, Act_20:32, Act_26:18, Rom_15:16, 1Co_1:2, 1Co_6:11, 1Co_7:14 (2), 1Ti_4:5, 2Ti_2:21, Heb_2:11, Heb_10:10, Heb_10:14, Heb_10:29, Jud_1:1
sanctify, 6
Joh_17:17, Joh_17:19, Eph_5:26, 1Th_5:23, Heb_13:12, 1Pe_3:15
sanctifieth, 4
Mat_23:17, Mat_23:19, Heb_2:11, Heb_9:13
hallowed, 2
Mat_6:9, Luk_11:2
There are some close correlations between holy (sanctified) and other similar words that are a continuing process. Hagiazō means to make holy, that is, (ceremonially) purify or consecrate; (mentally) to venerate: - hallow, be holy, sanctify. Hagios, from which hagiazō is derived means sacred (physically pure, morally blameless or religious, ceremonially consecrated): - (most) holy (one, thing), saint.
Hagiazō is to be. Hagios is declared.
Although one is derived from the other, they carry two different context. Care should be given to the context of the sentence and the word that is used.