to forget something accidentally
うっかり何かを忘れる (ukkari nanika o wasureru)
"Sorry, it completely slipped my mind to call you."
"ごめん、君に電話するのをすっかり忘れていた。" (gomen kimi ni denwa suru no o sukkari wasurete ita)
to choose not to participate
Use your time effectively and make the most of every moment.
to have a very good and friendly relationship
to make something less forceful or intense
to suddenly start sweating due to fear or anxiety
to go to ground; to take cover or hide
