expression, noun which may take the genitive case particle 'no'
all talk; insincere; empty words
Describes someone who says things without real intention or ability to follow through. Often used critically: 口先だけの人 (a person who is all talk).
彼の謝罪は口先だけだった。
His apology was just empty words.
口先だけの約束はしないでほしい。
I wish you wouldn't make promises that are just talk.
Compound of 口先 (lip service, superficial words) and だけ (only, just). The phrase literally means 'only the tip of the mouth', implying words without substance.