Akinfenwa chested down in the box and saw his deflected shot fly past Bobby Olejnik to continue Wycombe's impressive home form - they have lost just one of six league games at Adams Park this term.
Paul Hayes should have given the hosts the lead after 18 minutes when a bouncing ball fell to him five yards out but his looping header cleared the crossbar.
Exeter striker Reuben Reid's driven 27th-minute shot bounced dangerously in front of Wycombe keeper Jamal Blackman, who temporarily spilled, and the visitors were then denied a glorious chance as Ollie Watkins was penalised for a foul when one-on-one.
The Chairboys dominated the second period as substitute Akinfenwa nodded over and Paris Cowan-Hall flicked Joe Jacobson's delivery wide.
But after 85 minutes, Anthony Stewart's lofted ball from the left fell straight to Akinfenwa, allowing the big striker to turn and smash the ball past Olejnik for his second goal since joining the club.
Report supplied by the Press Association.
Match ends, Wycombe Wanderers 1, Exeter City 0.
Second Half ends, Wycombe Wanderers 1, Exeter City 0.
Corner,  Wycombe Wanderers. Conceded by Jordan Moore-Taylor.
Corner,  Wycombe Wanderers. Conceded by Craig Woodman.
Substitution, Wycombe Wanderers. Matt Bloomfield replaces Sam Wood.
Substitution, Exeter City. Liam McAlinden replaces Robbie Simpson.
Hand ball by Robbie Simpson (Exeter City).
Substitution, Exeter City. David Wheeler replaces Lee Holmes.
Goal!  Wycombe Wanderers 1, Exeter City 0. Adebayo Akinfenwa (Wycombe Wanderers) right footed shot from the centre of the box to the bottom left corner. Assisted by Anthony Stewart.
Jake Taylor (Exeter City) is shown the yellow card for a bad foul.
Scott Kashket (Wycombe Wanderers) wins a free kick in the defensive half.
Foul by Jake Taylor (Exeter City).
Substitution, Wycombe Wanderers. Scott Kashket replaces Paris Cowan-Hall.
Foul by Dan Rowe (Wycombe Wanderers).
Jake Taylor (Exeter City) wins a free kick in the defensive half.
Joe Jacobson (Wycombe Wanderers) is shown the yellow card for a bad foul.
Foul by Joe Jacobson (Wycombe Wanderers).
Ollie Watkins (Exeter City) wins a free kick in the defensive half.
Substitution, Exeter City. Pierce Sweeney replaces Jack Stacey.
Attempt blocked. Sam Wood (Wycombe Wanderers) left footed shot from the left side of the box is blocked.
Attempt missed. Paris Cowan-Hall (Wycombe Wanderers) header from the centre of the box is close, but misses to the right.
Joe Jacobson (Wycombe Wanderers) wins a free kick in the attacking half.
Foul by Jake Taylor (Exeter City).
Paris Cowan-Hall (Wycombe Wanderers) wins a free kick in the attacking half.
Foul by Luke Croll (Exeter City).
Attempt missed. Adebayo Akinfenwa (Wycombe Wanderers) header from the centre of the box is close, but misses to the right.
Substitution, Wycombe Wanderers. Adebayo Akinfenwa replaces Paul Hayes.
Corner,  Wycombe Wanderers. Conceded by Lloyd James.
Foul by Paul Hayes (Wycombe Wanderers).
Luke Croll (Exeter City) wins a free kick in the attacking half.
Corner,  Exeter City. Conceded by Joe Jacobson.
Dominic Gape (Wycombe Wanderers) wins a free kick in the attacking half.
Foul by Lloyd James (Exeter City).
Corner,  Wycombe Wanderers. Conceded by Jack Stacey.
Joe Jacobson (Wycombe Wanderers) wins a free kick in the defensive half.
Foul by Robbie Simpson (Exeter City).
Sam Wood (Wycombe Wanderers) wins a free kick on the right wing.
Foul by Jake Taylor (Exeter City).
Second Half begins Wycombe Wanderers 0, Exeter City 0.
First Half ends, Wycombe Wanderers 0, Exeter City 0.
Adebayo Akinfenwa's winner five minutes from time handed Wycombe a hard-fought 1-0 home victory over Exeter in League Two.