The term 'buckle under' is a phrase used to describe the act of giving in or submitting to a greater force. The crossword solutions for this term are YIELD (5 letters), CAPITULATE (10 letters), DEFER (5 letters), and BOW (3 letters). YIELD means to give up or surrender, while CAPITULATE means to surrender completely. DEFER means to put off or delay, and BOW means to bend at the waist in respect or submission. All of these words can be used to describe the act of buckling under to a greater force.