1. Can we say “an able teacher” as “a capable teacher”?
  2. Can we say “an abler teacher” as “a more capable teacher”?
  1. yes
  2. no. It would be ‘more able’

Should I not say “an abler teacher”?
Should I say only “a more able teacher”?
The syntax: ‘able - abler - ablest’ is not correct?
Is “a more capable teacher” OK?

  1. ‘Abler’ is a comparative form (though it is not in use as much as ‘more able’). It does not work well in your example. You cannot rule out the changes for context.

  2. yes

Hi Alifathima,

The form ‘abler’ would more often be used as a predicate - She is abler than most people give her credit for. The form ‘more able’ would be used as an epithet (before the noun) - She is a more able teacher than most give her credit for.

What does “most people give her credit for” mean?
Could you elaborate it a little more to understand?