Thanks for these, Jolan.
Your ingenuity is as devilish as ever. Wonderful clues.
Here is my stab at them.
1. University said to be unmistakable (8) – UNIVOCAL? (Uni – short for university, with vocal – said, gives univocal – in Chambers as unmistakable?)
2. A dogmatic pronouncement from courses taking in eleven with obtrusively religious upbringing? (4,5)- IPSE DIXIT? ( Tides – courses, taking in eleven – XI with Pi – obtrusively religious, all reversed (upbringing) gives ipse dixit- a dogmatic pronouncement?)
3. Upper-class people in the French line-up give vent to annoyance (3,3,5)- LET OFF STEAM? ( Toffs- upper class people, in “the” in French – Le , with team – line up gives “Let off steam”- vent annoyance?)
4. Like someone exposing Jacob abominably, he’s spare here (5,7)- SHEEP SHEARER? ( “Someone exposing Jacob” ( a type of sheep) is “he’s spare here” abominably- anagram of sheep shearer?)
5. Aggressively male about appearance? Then do not cut down a sabre-toothed tiger (12)- MACHAIRODONT? (Aggressively male – Macho, around air - appearance with “do not” cut down- don’t, gives Machairodont – a sabre toothed tiger?)
Thanks again.
AB