A. Synonyms for heavy

There are a number of adjectives similar in meaning to heavy. Note their typical contexts.

Adjective	Typical contexts	Example
weighty	abstract and physical things; usually includes the idea of ‘seriousness’	a weighty tome [large book]; discuss weighty issues
unwieldy	abstract and physical things; usually includes the idea of ‘difficult to handle’	an unwieldy system/bureaucracy; an unwieldy object, e.g. a big box
cumbersome	often used for machines and equipment that are difficult to handle; also for systems, structures, etc.	a cumbersome weapon; a cumbersome process
burdensome	usually used of abstract things	a burdensome duty
ponderous	slow and clumsy because of weight, but usually used for dull and excessively serious abstract things	a ponderous style, e.g. way of writing or speaking; a ponderous thesis
lumbering	usually used of physical things; often suggesting ‘heavy movement’	a lumbering truck; a lumbering bear

B. Phrasal verbs with weigh

I hate being weighed down with heavy suitcases when I travel. [carrying very heavy things]
She looked tired and weighed down with problems.
We’ll have to weigh up the alternatives before deciding. [consider and compare]
She weighed out a kilo of nuts and put them in a bag. [weighed a quantity of loose goods]
I have to confess something to you. It’s been weighing on me for ages. [troubling my mind]
The discussion was getting heated, and then Kate weighed in with some uncomfortable financial arguments. [added more points to the argument]

You can put some flour in to thicken the soup, but you should sift it first, or it will go lumpy.
The soup has been in the fridge so long it’s all congealed. [become thick and solid]
This curry powder is years old. It has completely solidified in the packet. [become solid]
Do you have some white spirit? I need to thin this paint. [make thinner]
As the rush hour ended, the traffic began to thin out. [become less dense]
The hairdresser thinned my hair out and it feels much lighter now. [made it less thick]
This fruit juice is very strong. Let’s dilute it / water it down a bit. [add water]

Word	Meaning	Literal use	Metaphorical use
impenetrable	impossible to move through	an impenetrable jungle/forest	impenetrable jargon
impervious	liquid cannot pass through	an impervious material, e.g. glass	a person who is impervious to criticism