Definition

1. Needed for a particular purpose: essential, necessary

(Ref: Merriam-Webster Online, Word of the day, 22 July 2020)

Use it in a sentence

Mr Tong, the substitute teacher, whistled quietly as he walked into the chaotic classroom. It was important to appear nonchalant, relaxed. He calmly placed his leather satchel on the desk, looked up briefly, but otherwise, concentrated on the task at hand. He pulled out some whiteboard markers, some note paper and pen, a small whistle, a miniature disco ball and finally a plush toy. All the requisite tools for teaching a year 6 class. They were cunning in this year level. They were confident and not so in awe of the year 7s. They positively lorded it over the year 4s and 5s, but they knew they weren’t the top dogs yet. They were, almost without exception, clever and obnoxious.

This is what Mr Tong had gleaned over many years. He also knew that the rowdiest rebels had to be quelled quickly, if they were to get any work done today. And he was determined that they would work. The children often sighed with palpable relief when they saw a substitute teacher walk in – a cruisy afternoon of reading or a leisurely game outside in the sunshine.

Not with this substitute teacher. Mr Tong picked up his plush toy, a blue elephant with a smart pink waistcoat, and looked around. He spotted a tall boy, hair rubbed carelessly to one side, one half of his shirt untucked, the other scrunched just under the waistband of his grey trousers. He guffawed loudly, not at all concerned by Mr Tong’s presence. The boy tipped his chair back, put his hands behind his head and smiled broadly at his friends, waiting to see how the day would pan out.

Mr Tong narrowed his eyes a moment, and then threw the elephant straight at the boy’s head.

The boy, startled and alarmed, scrabbled at the edge of his desk as his chair tipped further back. But he couldn’t save himself and clattered to the floor with a loud and indignant, ‘Oi!’ The rest of the class erupted into a nervous and hysterical laughter. 

Mr Tong smiled. That got their attention.