en_tn_condensed/jer/14/14.md

prophesy deceit

The word "deceit" can be expressed as an adjective. Alternate translation: "prophesy deceitfully" (See: rc://en/ta/man/jit/figs-abstractnouns)

in my name

This phrase refers to speaking with Yahweh's power and authority or as his representative. (See: rc://en/ta/man/jit/figs-metonymy)

I did not send them out

This means that Yahweh did not send them out with messages to give to the people. Alternate translation: "I did not send them to prophesy to other people" (See: rc://en/ta/man/jit/figs-explicit)

the deceitfulness of their hearts

"the deceitful things that they think up themselves"