This is the 2819th most frequent Japanese word.
頼り
Reliance; dependence; support.
The word '頼り' here refers to 'relying upon someone' and is used as a noun to signify the act of dependence.
彼はいつも私の頼りにしています。
He always relies on me.
In this sentence, '頼り' signifies reliability or trustworthiness, referring to the nature of the material.
この資料は頼りになります。
This material is reliable.
Here, '頼りなくて' conveys the state of being unreliable, showing the negative application of the term '頼り'.