Wiktionary
n. 1 Lack of emotion. 2 Lack of apparent emotion.
Usage examples of "flat affect".
Liysa maintained her flat affect when she learned that her husband was dead.
She tensed, though it was barely discernible from her other- 'wise flat affect.
And then she missed him too, his flat affect and his peculiar thought, like that of a large brilliant toddler, or a member of some other primate species, cousin to theirs: Homo scientificus.
Martha Laurens was to me no more than a name that caused a bloom of heat beneath the ice of my soul, and Joan Gwynne was an attractive, personable woman, given on occasion to spells of flat affect, who, according to other of my business associates, hadfollowing our brief flingseen the light of the White Goddess and was now an avowed lesbian with a live-in lover.