i Register
In some senses, lash is marked as obsolete, slang, British. Watch for register when choosing this word.
ADJ
bottom, lower | long, thick
VERB + LASH
bat, flutter
He fluttered his lashes dramatically when he was trying to get out of trouble.
lower
When she felt shy, she would lower her lashes and look down at her feet.
LASH + VERB
flicker, flutter
His lashes fluttered nervously as he waited to hear the exam results.