'Convince someone of something' = to make them believe. 'Convinced his father of his plan.'

'Arrive at a compromise/decision/conclusion' = standard English idiom.

A knife's 'blade' is what cuts. 'Edge' refers to the sharpened side of the blade.

Imperative passive: 'Let + object + not + be + past participle'.

Passive of command (let + object + be + past participle): 'Let the door be opened.'

'One of the best players that' — relative pronoun refers to 'players' (plural) → 'have'.

'Killed himself' = reflexive. No passive needed. Simple past reflexive.

Third conditional: 'If + past perfect → would + have + past participle'. 'Would not have done'.

'Put the cart before the horse' = to do things in the wrong sequence.

'Blue blood' = aristocratic or noble descent.

'White elephant' = a costly or burdensome possession that is useless.

'Efface' = to wipe out or erase. Synonym: 'Rub out'.

'Oblivion' = the state of being forgotten. Synonym: 'Forgetfulness'.

Present/habitual: 'talks as if he knew' is technically correct but 'He talks as if he knows' is also accepted in informal usage.

'Milk' is uncountable → 'little/a little'. 'A little' means some; 'little' = hardly any. 'little' fits implying scarcity.

Antonym analogy: Eager↔Indifferent. Similarly Enthusiastic↔Halfhearted.

Synonym analogy: Lengthen≈Prolong. Similarly Stretch≈Extend.

Synonym analogy: Delay≈Retard. Similarly Slow down≈Hold up.

Antonym analogy: Submissive↔Disobedient. Similarly Observe↔Defy.

'Fantasize about' is the correct collocation.