What is the meaning of Weak_verb?

One of a class of verbs which use a dental suffix appended to the stem to indicate the past tense.

1. A regular verb of this class (thus excluding verbs that do have a dental suffix, but show some formal peculiarity, as in tell > told).

A regular verb of this class (thus excluding verbs that do have a dental suffix, but show some formal peculiarity, as in tell > told).

A member of a verb class that is customarily called “weak”, and usually distinguished from another class called “strong”.

1. A verb formed from a root that includes a semivowel or another consonant prone to elision (so-called “weak roots”).

A verb formed from a root that includes a semivowel or another consonant prone to elision (so-called “weak roots”).

Source: wiktionary.org