Preterite and imperfect

Imperfect: the Past Tenses. In very general terms, the preterite tense is used to refer to a single event that happened at a specific point of time or had a specific duration in the past, while the imperfect tense is used to describe ongoing events or events without a specific time period in the past.

a word that has the same meaning as another word is a synonym

Explanation:

for example a synonym of strong would be powerful since they nearly have the same meaning