1.
relying on others; dependence on others; leaving things to others
In everyday usage, describes the attitude of depending on others to do things for you rather than making an effort yourself. Carries a negative connotation of laziness or lack of initiative.
他力本願ではうまくいかない。
It won't work out if you just rely on others.
他力本願ではなく、自分で努力すべきだ。
You should make an effort yourself, not rely on others.
彼はいつも他力本願で、自分からは何もしようとしない。
He always depends on others and never tries to do anything himself.
2.
salvation through Amida Buddha's power (Buddhist term)
The original Buddhist meaning: the belief in Pure Land Buddhism that salvation comes through the power (他力) and original vow (本願) of Amida Buddha, rather than through one's own efforts.
浄土宗では他力本願が教えの中心である。
In Pure Land Buddhism, reliance on Amida's power is central to the teachings.
他力本願の思想は親鸞によって広められた。
The concept of salvation through Amida's vow was spread by Shinran.
本来の他力本願は仏教用語であり、他人任せという意味ではない。
The original meaning of tariki hongan is a Buddhist term, not 'leaving things to others.'
A 四字熟語 with a notable gap between its original Buddhist meaning and its everyday usage. In everyday Japanese, it is almost always used in sense 1 with a negative connotation. Buddhist scholars sometimes object to this colloquial usage, noting that the original meaning (sense 2) refers to a profound religious concept in 浄土真宗 (Jodo Shinshu Buddhism). The opposite concept is 自力 (relying on one's own efforts).