ἐνθυμέομαι - "to consider, ponder"
from ἐν “in” + θυμός “mind, heart”
Hence, “to have in mind” or “to bear in mind”
The essential meaning of θυμός is the “vital spirit” or “breath of life” - that which makes us rational creatures like our Creator. This is the basic sense in this compound verb.
There has been some speculation that this verb might connote “to be angry”. This misunderstanding is due to the importing of the subsequently derived and subsidiary sense of θυμός - “passion, anger” - into this compound verb which knows nothing of it. It simply employs the basic meaning of “mind” or “heart.” Here is an example of an all too common exegetical fallacy.
Examples: Matt. 1.20, Matt. 9.4
