The Times Croswword, 25631, Can You Help With The Answers?

[dprjones]

I have only recently started doing The Times cryptic crossword.

I am amazed that I have finished this one. It is one of the first I have ever finished! I am sure, (in fact I know), that it was more by chance than judgement.

There are a number of clues that I ending up guessing at rather then fully understanding the clues. They were for example:

20a. Number of letters in Post Office by five (5). Which I have to conclude, given the other letters I have, is "Fifty" - but why?

26a. Awkward in test if failing (5). Which I think is "Stiff" but, again, I can't see why.

11a. It can be the equivalent of best, verbally! (5). I have as "worst" but would like confirmation as to why.

Finally, 1a. I'm not happy about why it appears to be "accost".

All help is appreciated. As I stated above, I have only recently started with cryptic crosswords. Is there a useful internet site that explains the abbreviations, codes et al used in these cryptic clues?

Thank you in advance to all who respond.

[jeffa]

20a There are ten letters in 'post office' and ten by five = 50.

26a teST IF Falling

11a Because it’s the opposite of “best” and also synonymous with it. “verbally” = “in words”.

1a ACCOST sounds like "a cost" - easiest clue for ages!

[dprjones]

That's very quick! And very helpful!

Thank you very much!

[dprjones]

Could I trouble you for another that I was uncertain about?

25a. Liberal accepted, within reason? Possibly in European City.

I got "L" for Liberal; and an anagram or "reason" but didn't understand the "European" bit - and ended up with "Orleans". Did I get it wrong? Did I get it right by chance and mis-understanding?

[scorpiojo]

L + reason - Orleans is in France

[dprjones]

Ah!

Thank you. I was trying to fit that "E" in somewhere!

Please forgive my ignorance, and thank you.

[scorpiojo]

You're welcome

[Pantagruel]

Try the times for the times website- answers and parsing every day.