Building blocks
ehma- "ehm-", carries the idea of a sudden shock or fright
-ta- - causative (“make something be X”)
-ma - infinitive ending
So, "ehmatama" essentially means "to cause someone to feel startled or scared."
How to use it
To Startle or Scare Someone:
Film oli väga pingeline ja ehmatas mind mitu korda.
Translation: The movie was very tense and startled me several times.
To Suddenly Feel Fear or Get startled:
Ma ehmatasin, kui auto järsult pidurdas.
Translation: I got scared when the car braked suddenly.
What to remember when using the verb “ehmatama”:
The person you scare or startle is in the Partitive Case (third base form)
Examples
Telefoni ootamatult vali helin ehmatas töötajat
Literally: “Phone unexpected-from loud ring startled employee”
Idiomatically: “The unexpectedly loud ring of the phone startled the employee”
Telefoni - Noun - Genitive Sg, "Phone"
ootamatult - Adverb - Indeclinable, "unexpectedly"
vali - Adjective, Nominative Sg, "loud"
helin - Noun - Nominative Sg, "ring"
ehmatas - Verb - 3P Past Sg, "startled"
töötajat - Noun - Partitive Sg, "employee"