נאם To speak in a low voice, whisper, speak softly. This is akin to נא Strongs #4994 meaning “please” or “pray thee.”
Throughout the Prophets, a reader will encounter the Hebrew נאם in a consistent form 375 times. Most Hebrew verbs are used in many forms and conjugations. A Hebrew verb can technically be conjugated in over a 120 ways. However, this not insignificant form is conjugated in only one way as נאם, with the exception of one instance as נאום in Jeremiah 7:30 and one instance in Jeremiah 23:31.
The verb נאם has been interpreted as a noun based on the perceived context (i.e. an utterance of YAHWEH). Beyond this there is no grammatical indication found anywhere of its signification as a noun. As a verb, it is readily acknowledged as being used as such (cf. Strong’s #5001):
Behold myself upon the Prophets, HE IS he who whispers [נאם], the Takers of tongues of themselves, and they are whispering [ינאמו], “He has whispered [נאם]!”
(Jeremiah 23:31 RBT)
This verse gives away the sense and form of the respective verb and conjugation in no uncertain terms. נאום has one of two meanings. An infinitive absolute, or a passive participle. 
נאם, similarly has the meaning of an infinitive or active participle, or 3rd person masculine complete, or imperative 2nd person masculine singular.
Gesenius notes the passive participle “he who whispers” as the most frequent use:
