Similar meaning (3)

Can anyone please clarify the difference between the words: important, significant, substantial and considerable for me?

Thanks in advance.

Important is something that is of great significance.

Significance is something worthy of attention. (significant and important can be synonyms).

Substantial can mean important but it can also mean something that is large in size or worth a great deal of money. (The car has substantial value.  The house is of substantial size)

Considerable can mean of great size (He has is in a position of considerable influence). It can also mean distinguished (He is a considerable doctor, worthy of admiration).

Hope this helps!