blank on

blank on (third-person singular simple present blanks on, present participle blanking on, simple past and past participle blanked on)

1. (transitive, informal) To be temporarily unable to remember (a particular fact).

   Synonyms: freeze on, freeze up on

   I’m blanking on her name right now.

• Also used with the particle out inserted:
  The entire class blanked out on the third question on the test.
• Commonly used in the first person, present progressive tense.