IPA: /ɪnˈsɒm.ni.æk/
KK: /ɪnˈsɑmniˌæk/
Describing someone who has difficulty sleeping or suffers from insomnia.
She is an insomniac who often struggles to fall asleep at night.
A person who has difficulty sleeping and often cannot fall asleep or stay asleep.
As an insomniac, she often found herself awake at night while others were sleeping.
Insomniac → It is formed from "in-" (meaning not) and "somnus" (meaning sleep) combined with the suffix "-iac" (indicating a person affected by a condition). The word describes a person who is not able to sleep, hence an insomniac is someone who suffers from insomnia.
Think of 'not' ('in-') being combined with 'sleep' ('somnus') to remember that an insomniac is someone who cannot sleep.