to hold back; to refrain; to politely declineUsed when holding back out of politeness or consideration, or when politely declining an offer. 遠慮せずに means “don't hesitate,” and 遠慮しとく means “I'll pass.”
JA: 質問があれば、遠慮する必要はありません。
EN: If you have any questions, you don't need to hesitate.