Abarim Publications' online Biblical Hebrew Dictionary
דקר
The verb דקר (daqar) means to pierce or thrust through, always of human beings and usually with the result of death (Judges 9:54, 1 Samuel 31:4, Isaiah 13:15), but sometimes leaving the person alive and badly wounded (Jeremiah 37:10).
The instrument mostly associated to this verb is the sword, but in Numbers 25:8, Phinehas runs Zimri and Cozbi through with a spear. In Lamentations 4:9, Jeremiah observes that it is better to be pierced with a sword than with hunger. Via prophet Zechariah, YHWH famously foretells that the house of David would look mournfully on him who they would have pierced (Zechariah 12:10).
This verb comes with one derivative, namely the feminine noun מדקרה (madqara), meaning a piercing. It occurs only once, in Proverbs 12:18, where thoughtless speech is equated with the piercing of a sword.